DEPARTMENT OF THE INTERIOR 

UNITED STATES GEOLOGICAL SURVEY 

GEORGE OTIS SMITH, Director 

Water-supply Paper 345— H 



GROUND-WATER RESOURCES OF THE NILES CONE 
AND ADJACENT AREAS, CALIFORNIA 

BY 

W. O. CLARK 



Prepared in cooperation with the 
Department of Engineering of the State of California 



Contributions to the Hydrology of the United States, 1914 — H 




WASHINGTON 

GOVERNMENT PRINTING OFFICE 
1915 



Monograp\\ 



\ 



DEPARTMENT OF THE JNTERIOR 

UNITED STATES GEOLOGICAL SURVEY 

GEORGE OTIS SMITH, Director 



"Water- Supply Paper 34:5— H 



GROUND- WATER RESOURCES OF THE NILES CONE 
AND ADJACENT AREAS, CALIFORNIA 



BY 



W. O. CLARK 



Prepared in cooperation with the 
Department of Engineering of the State of California 



Contributions to the Hydrology of the United States, 1914— H 




WASHINGTOK 

GOVERNMENT PRINTING OFFICE 
1915 



d; fF D. 

APft S3 1915 



03 



)0>5 



Q^e(« 






CONTENTS. 



Introduction 127 

Location and area 127 

Agricultural development 127 

Purpose of this report 128 

Acknowledgments 128 

Physiography and drainage 128 

Mountain area 128 

Valley area 130 

Precipitation and run-off 132 

Geologic formations in relation to ground water 144 

Outline of formations 144 

Jurassic (?) system 144 

Franciscan group 144 

Cretaceous system 145 

Knoxville and Chico formations 145 

Tertiary system 145 

Eocene series 145 

Tejon formation 145 

Miocene series 145 

Monterey group 145 

Pliocene series 145 

Orinda formation 145 

Tertiary or Quaternary system 146 

Santa Clara formation 146 

Quaternary- system 146 

Pleistocene and Recent series 146 

Allu\'ium underlying the interior valleys 146 

Alluvium underlying Santa Clara Valley 147 

Origin of ground water 149 

General source 149 

Influence of the Niles-Irvington fault 149 

Water-level data 151 

Interpretation of the data 153 

Contributions to the ground-water supply 158 

Withdrawal of ground water 162 

Spring Valley Water Co '. 162 

People's Water Co 162 

Irrigation 162 

Loss by evaporation on the salt marsh 163 

Seepage into the bay 164 

Relation of withdrawals to contributions 164 

Incursion of sea water 165 

Summary of conclusions 166 

III 



ILLUSTRATIONS. 



Plate IX 

X 
XI 



XII 

XIII. 

XIV 

XV 

XVI 

XVII 

Figure 9. 
10. 

11. 

12. 
13. 
14. 
15. 
16. 
17. 
18. 
19. 
20. 
21. 
22. 
23. 
24. 



Map of the Alameda Creek drainage basin, Cal., and adjacent 

areas In pocket. 

Map of the Niles cone, Cal., and adjacent areas In pocket. 

A, View of Niles cone, Cal., showing its regular topography and 
slight gradient; B, Niles-Irvington fault scarp, Cal., with The 

Lagoon in the foreground 130 

Notch in fault scarp at Tule Pond, Cal., representing ancient stream 

channel cut off by the displacement 132 

A and B, Ancient drainage channel broken by displacement along 

Niles-Irvington fault, Cal 133 

Well sections along line 0-P, Plate X 148 

Well sections along line Q-R, Plate X 148 

Well sections along line S-T, Plate X 148 

Well sections along line U-V, Plate X 148 

Map showing submerged stream channels in San Francisco Bay, Cal. 131 
Diagram showing effect of topography on rainfall in California and 

Nevada 133 

Diagram showing effect of topography on rainfall in the Coast Range 

of California 133 

Profiles of water table along line F-G, Plate X 150 

Graph showing fluctuation of water table along line F-G, Plate X. . 150 

Graph showing fluctuation of water table along line A-B, Plate X. . 153 

Graph showing fluctuation of water table along line A-C, Plate X. . 153 

Graph showing fluctuation of water table along line D-E, Plate X. . 154 

Graph showing fluctuation of water table along line H-E, Plate X. . 155 

Graph showing fluctuation of water table along line I-J, Plate X. . 155 

Graph showing fluctuation of water table along line K-L, Plate X. . 156 

Profiles of water table along line M-N, Plate X 157 

Graph showing fluctuation of water table along line C^, Plate X... 158 

Graph showing fluctuation of water table along line C2, Plate X. . . 159 

Graph showing fluctuation of water table along line C3, Plate X. . . 160 

Graph showing fluctuation of water table along line C4, Plate X. . . 160 



GROUND-WATER RESOURCES OF THE NILES CONE AND 
ADJACENT AREAS, CALIFORNIA. 



By W. O. Clark. 



INTRODUCTION. 

Location and area. — The area covered in detail by this report 
comprises the Niles cone and adjacent tracts in Santa Clara Valley, 
Cal., just east of the south end of San Francisco Bay. The drainage 
basins of Alameda Creek and other streams tributary to this valley 
area are also described in respect to the conditions that influence 
its ground-water supply. (See PL IX, in pocket.) 

The Niles cone, which is built of the alluvial deposits of Alameda 
Creek, is bounded on the north by a line that extends from the 
town of Niles to a point about half a mile north of Alvarado, and on 
the south by a line that extends from Niles to Jarvis Landing, 
approximately as shown in Plate IX. The tract between the Niles 
cone and a line extending from Mission San Jose through Irvington 
and a point on the Southern Pacific Railroad about 1 mile southeast 
of Mowry station is physiographic ally not a part of the cone but is 
intimately related to it in regard to ground- water supplies. The 
cone and this adjacent tract are cut by a fault, shown in Plates IX 
and X (in pocket), which profoundly influences the ground-water con- 
ditions. The cone covers about 11,800 acres, and the part of the 
additional tract lying west of the fault covers about 9,000 acres, both 
exclusive of the salt marsh. The estimates of ground w^ater given 
in this report refer to the 20,800 acres of the cone and that portion 
of the adjacent tract that lies west of the fault. 

Agricultural development. — The region about Niles is one of inten- 
sive cultivation. The holdings are for the most part small, being 
tracts of 5, 10, 20, or 40 acres. Nearer the bay the holdings are as 
a rule considerably larger, many of them comprising from 100 to 
several hundred acres. Here the cultivation is less intensive, the 
crops being largely oats, barley, and alfalfa. In many places near 
the salt marsh these crops give way to pasture lands. The acreage 
of alfalfa is rapidly increasing, and in a short time much of the oat 
and barley land will probably be converted into alfalfa fields. This 
change will increase the amount of water needed for irrigation. 

127 



128 CONTRIBUTIONS TO HYDKOLOGY OF UNITED STATES, 1914. 

The areas covered by different crops in 1913 were plotted and 
measured for the Niles cone and a small additional area and were 
estimated for the remaining part of the related tract west of the 
fault shown on Plate X. The acreage of the different crops west of 
the fault thus determined is as follows: Orchard, 2,900 acres; toma- 
toes, 1,350 acres; potatoes, 380 acres; other vegetables, 1,300 acres; 
corn, 340 acres; sugar beets, 75 acres; strawberries, 65 acres; peas, 
25 acres; nursery, 550 acres; alfalfa, 2,430 acres; oats and barley, 
5,170 acres; and pasture, 5,560 acres. 

Purpose of this report. — For more than 20 years there has been 
contention between the people in the vicinity of Niles and the water 
companies that take large supplies from the Niles cone and tributary 
drainage basins to San Francisco and other cities on the bay. The 
farmers of the vicinity have recently been organized into a water dis- 
trict, and further litigation with the water companies is in prospect. 

This report is based on an investigation in which an attempt was 
made to determine the source of the ground water, the quantity 
now being withdrawn, the amount available, and the area dependent 
on Alameda Creek. 

Acknowledgments. — Acknowledgments are especially due to Mr. 
O. E. Meinzer, Dr. J. C. Branner, and Dr. J. P. Smith for much 
valuable help in the preparation of this report. The writer is also 
indebted to the Spring Valley Water Co., the People's Water Co., 
and the Southern Pacific Co., for much valuable information, also 
to Mr. J. H. Forbes, who ran levels and kept records of many wells 
for the Spring Valley Water Co., and to the many residents of the 
district for their kind cooperation in the collection of well records, 
without which much of the detail of this report could not have 
been presented. 

PHYSIOGRAPHY AND DRAINAGE. 

MOUNTAIN AREA. 

Northeast of the Santa Clara Valley lie the Contra Costa and 
Mount Hamilton ranges, which have an average elevation of approxi- 
mately 2,000 feet above sea level and in Copernicus Peak reach an 
altitude of 4,372 feet. Among the mountains back of the steep 
front that faces the Santa Clara Valley lie a number of open valleys, 
which, although not as large as the Santa Clara Valley, are of con- 
siderable size. About 640 square miles of this region of mountains 
and interior valleys is drained by Alameda Creek, which emerges 
from the mountains at the town of Niles and discharges upon the 
Niles cone. (See PL IX.) Smaller mountain areas are drained by 
several smaJl streams or canyons to the valley tracts that lie adjacent 
to the Niles cone. Dry Creek, northwest of Alameda Creek, has a 
drainage area of approximately 9 square miles; Mission Creek, south- 



GROUND-WATER RESOURCES OF NILES CONE, CAL. 129 

east of Alameda Creek, has a drainage area somewhat less than that 
of Dry Creek. Mission Creek and the smaller streams between it 
and Alameda Creek have furnished the sediments that underlie the 
area south of the Niles cone and west of the fault line. 

The principal interior valleys within the Alameda Creek basin are 
the Livermore Valley, with its two arms — Amador and Las Positas 
valleys — the Sunol Valley, the Calaveras Valley, and the Isabel Valley. 
The Livermore Valley is larger than the others combined. These are 
all open valleys, surrounded by mountains. They apparently owe 
their existence in large part to the extensive faulting and other earth 
movements by which this region has been affected in recent geologic 
time. 

The Alameda Creek drainage system comprises two main branches 
which, flowing almost directly toward each other, join in the vicinity 
of Sunol, and thence discharge their united waters through a canyon 
that is about 6 miles long and that has its outlet at Niles. The south 
branch, which carries the name of Alameda Creek, receives the 
drainage of Calaveras Creek, San Antonio Creek, and several smaller 
streams. The north branch, known as Arroyo de la Laguna, is the 
outlet of the Livermore Valley, into which discharge several rela- 
tively large streams, most important of which are Arroyo del Valle 
and Arroyo Mocho. 

Alameda Creek rises on the northern slopes of Packard Ridge, a 
few miles north of Mount Hamilton and just east of Rattlesnake 
Butte, which has an elevation of 3,444 feet above sea level. 

Calaveras Creek has a drainage area of approximately 100 square 
miles. Its principal tributary, Arroyo Hondo, is formed by the 
junction of Isabel and Smith creeks. Isabel Creek rises near the 
boundary hne between Santa Clara and Stanislaus counties, flows 
through Isabel Valley, passes round Mount Hamilton on the east 
and north, and joins Smith Creek about 4 miles northwest of Mount 
Hamilton. Smith Creek rises on the western slopes of Pine Ridge, 
at an elevation of about 3,400 feet, and passes west of Mount Hamil- 
ton, to its junction with Isabel Creek- From the junction Arroyo 
Hondo leads to the lower end of Calaveras Valley, where it discharges 
into Calaveras Creek. The united waters then pass through about a 
mile of steep-walled canyon and discharge into Alameda Creek. 
Although Arroyo Hondo is said to discharge into Calaveras Creek, 
the water carried by the Calaveras above the confluence is practically 
negligible. 

San Antonio Creek, which discharges into Alameda Creek from the 
east, a short distance above Sunol, has a drainage area that covers 
about 35 square miles and lies at elevations ranging from 500 to 3,600 
feet above sea level. 



130 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1914. 

Arroyo del Valle, which discharges, through the southern part of 
Livermore Valley, into Arroyo de la Laguna, receives the drainage of 
about 150 square miles — the largest single unit in the Alameda basin. 
Its headwaters are on the borders of Santa Clara and Stanislaus coun- 
ties, 2,500 to 3,000 feet above sea level. 

Arroyo Mocho, which also discharges into the Livermore Valley, 
has a drainage area of approximately 50 square miles. It has its 
source about the four corners of Alameda, San Joaquin, Stanislaus, 
and Santa Clara counties. For most of its course it flows through a 
region that is from 2,500 to 3,000 feet above sea level. 

Among the other streams, discharging into the Livermore Valley, 
the largest are Arroyo las Positas and Arroyo Seco. 

VALLEY AREA. 

In contrast to the rugged mountain area above described the Santa 
Clara Valley appears exceedingly flat and monotonous. (See PI. XI, 
A.) Yet it has its own features, which, although not so striking as 
those of the mountain area, are quite as distinctive and significant. 
The valley area covered in this report consists essentially of the Niles 
cone and the alluvial cones or fans of Mission Creek and other small 
streams. The slope of all these alluvial cones is very gentle, being on 
an average only about 10 feet to the mile. The gentleness of the 
slope shows that water has been abundant during the process of 
alluvial filling, for cones built under conditions of meager water sup- 
ply are invariably steeper, many of them having slopes of as much as 
500 feet to the mile. 

Among the several aUuvial cones in this vicinity the Niles cone is 
small in comparison with the relatively large drainage basin tributary 
to it, but this condition is due partly to the fact that the materials of 
the cone were derived largely from the 15 to 20 square miles of the 
Alameda Creek drainage basin lying southwest of Livermore VaUey, 
most of the alluvial material derived from the remaining 620 or 625 
square miles of the basin being left behind in the Livermore, Sunol, 
and other valleys. 

A conspicuous and significant topographic feature in this nearly 
flat area is an escarpment formed by recent faulting. This escarp- 
ment, which faces the mountains and trends N. 35° W., crosses a 
reentrant of the valley and cuts off the apex of the Niles cone as well 
as some of the flat land to the south. It begins in the vicinity of 
Tule Pond and extends past The Lagoon to the town of Irvington. 
It ranges in height from only a few feet to 20 or 25 feet at its highest 
point, at The Lagoon (Pis. X and XI, 5). A distinct ridge approaches 
this escarpment from the west in the vicinity of The Lagoon, as if 
there had been some thrusting force and a slight buckling at the time 
of faulting. Behind this escarpment are two ponds — The Lagoon, 



U. S. GEOLOGICAL SURVEY 



WATER-SUPPLY PAPER 345 PLATE XI 




A. VIEW OF NILES CONE, CAL., SHOWING ITS REGULAR TOPOGRAPHY AND SLIGHT GRADIENT. 




JB. NILES-IRVINGTON FAULT SCARP, CAL., WITH THE LAGOON IN THE FOREGROUND. 



GROUND-WATER RESOURCES OF NILES CONE, CAL. 



131 



which when full has an area of 200 to 300 acres, and Tule Pond, which 
probably at no time covers more than 50 acres. These ponds were 
never known to be entirely dry until the summer of 1913, near the close 
of the two-year period having a lighter precipitation than any other 







Raven $wood Pt 



^ 



Dumbarton 
Pt 




2 Miles 



Figure 9.— Map showing submerged stream chamiels in San Francisco Bay, Cal. (From Coast and 

Geodetic Survey.) 

two consecutive years on record. They are, however, always shallow 
and vary greatly in extent with the season. Southwest of the ponds 
rises the relatively abrupt fault scarp, but to the northeast there is 
no perceptible bank except at the northern shore of Tule Pond, where 

70933°— 1.-) 2 



132 CONTRIBUTIONS TO HYDKOLOGY OF UNITED STATES, 1914. 

there is a small cliff that is probably due partly to erosion b}^ water 
entering at that end and partly to wave action. On the side toward 
the mountains the land rises very gradually to the steep front of the 
mountains. 

This fault scarp has caused considerable change in drainage. (See 
PI. X.) The so-called Laguna drainage basin, which should not be 
confused with the Arroyo de la Laguna that forms the outlet of the 
Livermore Valley, consists of all of the area tributary to The Lagoon 
and comprises several small units south of Alameda Creek. (See 
PI. IX.) This drainage basin is now limited on the west by the fault 
scarp, but before the recent movement along tiie fault its waters dis- 
charged over the flat land west of the fault and south of the Niles cone 
and supplied the sediments underlying this land. Mission Creek, 
coming from the hills, flows northwestward into The Lagoon, but the 
stream that forms the outlet of The Lagoon has a southeasterly course 
and makes an angle of only about 60° with Mission Creek. A notch 
in the escarpment, shown in Plate XII, represents an abandoned 
stream channel (PI. XIII, A), which is distinctly marked from this 
point to the place where it enters the salt marsh, just south of the 
Little Coyote Hills. In Plate XIII, B, is shown a similar ancient 
stream channel which is not so sharply defined as this one but is never- 
theless distinct. It starts at a notch in the escarpment near the north 
end of The Lagoon and can be traced to a point about a mile south- 
west of Newark, beyond which it has been artificially straightened. 
Both these ancient drainage lines are shown on Plate X. 

At the foot of the Niles cone and extending somewhat farther 
south are two groups of rock hiUs known as the Coyote Hills and the 
Little Coyote HiUs, which are separated from each other by a gap of 
salt marsh only about half a mile wide. (See Pis. IX and X.) The 
Coyote HiUs reach an elevation of a little more than 290 feet, and 
the Little Coyote Hills only about 50 feet. The salt marsh gap 
separating these two groups of hills is the inlet of Newark Creek, or 
the outlet of Sanjen de los Alisos, which at no very remote date was 
the main Alameda Creek. Its old channel is traceable for some dis- 
tance beneath the waters of the bay. Coyote HiU Creek, at the north 
end of the Coyote' HiUs, is also an ancient outlet of Alameda Creek, 
and its channel is distinctly traceable for a mile or more beneath the 
bay. (See fig. 9.) 

PRECIPITATION AND RUN-OFF. 

The Contra Costa and Mount Hamilton ranges are effective rain 
producers. They lie at right angles to the path of the prevailing 
moisture-laden winds from the Pacific and are of sufficient height 
to cause considerable condensation from these winds. Though their 
rainfaU is less than that of the humid parts of the United States it 



U. S. GEOLOGICAL SURVEV 



WATER-SUPPLY PAPER 345 PLATE XIII 




A. 




ANCIENT DRAINAGE CHANNEL BROKEN BY DISPLACEMENT ALONG NILES-IRVINGTON FAULT, CAL. 



GROUND-WATER RESOURCES OF NILES CONE, CAL. 



133 



is heavy at certain times during the winter, when the air coming 
from the ocean nearly saturated is forced over the mountains and 
thereby cooled. Consequently Alameda Creek is subject to heavy 
floods. 

There is a marked increase in rainfall with altitude. McAdie/ 
quoting records obtained in the vicinity of Fresno, Cal., gives the 



SIERRA NEVADA 

47 rim 



PACIFIC 
OCEAN 



SACRAMENTO VALLEY 



p ,, ,u San Francisco Fairfield Sacnunento YoUm 




C ^" ""' eSm/es 50 75 100 125 ISO 175 "*'■'' "■""'V^O ??5 250 

Figure 10.— Diagram showing effect of topography on rainfall in California and Nevada. After Hamlin 

rate of increase as 1.18 inches of rainfall to 100 feet of altitude, and 
he calculates from further data for the season of 1911-12 a differ- 
ence of 1 inch in 100 feet.^ Hamlin ^ shows the effect of topography 
on rainfall by means of the diagrams given in figures 10 and 11. 
On Mount Hamilton, 4,209 feet above sea level, the average annual 
precipitation, according to United States Weather Bureau records, 



PACIFIC 
OCEj\S 



SANTA 
LUCIA 
RANGE 



MT DIABLO RANGE 
SALINAS GALLEY ,SL/7,n 

*"> I Priest Valley 



SAN JOAQUIN VALLEY 




Figure 11.— Diagram showing effect of topography on rainfall in the Coast Range of California. After 

Hamlin. 

is 31.42 inches (p. 137). Twice in January, 1911, there were heavy 
downpours on this mountain. During one of these storms 9.19 
inches feU in 24 hours and during the other 5.56 inches fell in an 
equal time.^ Arroyo Hondo, which drains all sides of the lofty 
mountain mass that culminates in Mount Hamilton and Copernicus 

1 McAdie, A. G., U. S. Dept. Agr. Monthly Weather Review, vol. 39, No. 9, September, 1911. 

2 McAdie, A. G., Rainfall of California: California Univ. Pubs., vol. 1, No. 4, p. 158, Feb. 19, 1914. 

3 Hamlin, Homer, Water resources of the Salinas Valley, California: U. S. Geol. Survey Water-Supply 
Paper 89, pp. 41, 42, 1904. 

< McAdie, A. G., Rainfall of California: California Univ. Pubs., vol. 1, No. 4, p. 179, Feb. 19, 1914. 



134 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1914. 

Peak and also other large areas with high altitudes, is the best water 
producer in the Alameda system. According to records of the Spring 
Valley Water Co.^ the annual discharge of Arroyo Hondo at the 
Calaveras dam site, in the canyon below Calaveras Valley, for the 
five consecutive seasons from 1898-99 to 1902-3, was 15,535 million 
gallons, or 47,675 acre-feet; and for the nine seasons for which 
records ^ are available almost 19,689 miUion gallons, or 60,423 
acre-feet. This 9-year record is not a continuous one, there being 
a break of one year between the 5-year period 1898-1903 and the 
4-year period 1904-1908. 

The only available records of the discharge of San Antonio Creek 
are those from January to June, inclusive, 1912, given by the Spring 
Valley Water Co.^ The total discharge during this period was 
reported to be 454 milhon gallons, or about 1,393 acre-feet. Accord- 
ing to records "of the Southern Pacific Co. and the Spring Valley 
Water Co. the mean annual rainfall at Sunol during a period of 23 
years was 22.26 inches. The minimum for any one season was 10.5 
inches (1897-98) and the maximum 38.99 inches (1889-90). 

The meager records of rainfall in the region tributary to Arroyo 
del Valle range from 18 to 43 inches a year. The Spring Valley 
Water Co.,^ by its method of interpolation (for the correctness of 
which the writer does not vouch), estimates the mean annual rainfall 
for the entire Arroyo del Valle drainage area at 20.80 inches. The 
average annual run-off at the dam site of the Spring Valley Water 
Co., about 3i miles above the point where Arroyo del Valle enters the 
LiYermore Valley, during a period of four seasons, from 1904-5 to 
1907-8, inclusive, as computed by the writer from data given by 
the company,^ was 14,050 miUion gallons, or 43,118 acre-feet. 

There are no records of rainfall in the area tributary to Arroyo 
Mocho. At Livermore, 487 feet above sea level, the Government 
records show the average annual rainfall for 42 years to be 15.49 
inches (p. 138), but the average altitude of the area tributary to 
Arroyo Mocho is much greater than that of Livermore, and its rain- 
fall is therefore heavier. According to the records of the Southern 
Pacific Co. the average annual rainfall at Pleasanton during a period 
of eight years was 16.03 inches (p. 139). A 13-year record of the 
Spring Valley Water Co.^ for a point about 2 miles southeast of 
PJeasanton gives the average annual rainfall as 25.21 inches. 

1 The future water supply of San Francisco from the conservation and use of its present resources, p. 323, 
Oct. 31, 1912. 

2 Idem, p. 113. 

3 Idem, p. 342. 

i Idem, p. 284a. 
5 Idem, p. 292. 



GROUND-WATER RESOURCES OF NILES CONE, CAL. 



135 



In the following tables are given the available records of precipi- 
tation at stations in or near the Alameda Creek- drainage basin and 
the Spring Valley Water Co.'s records, of discharge of Alameda 
Creek at the Sunol dam, and also the discharge over Brightside 
weir. The Brightside weir is situated in Alameda Canyon, between 
1 and 2 miles below the Sunol dam. The water flowing over this 
weir is ground water that has been pumped by the Spring Valley 
Water Co. and is on its way to San Francisco. Because this water 
would rise, in large part, and flow thi'ough Alameda Creek to the 
Niles cone it has been added to the flow of that creek in the table 
on page 143. The discharge records were generously furnished to 
the United States Geological Survey by the Spring Valley Water Co. 

Records of precipitation in or near the Alameda Creek drainage basin {in inches). 

Alvarado, Alameda County, a 

[Elevation 19.5 feet.] 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dee. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total 

for 
season. 


1906 




















0.85 
.12 

1.10 


.47 
.74 

1.66 
.59 
.73 


1.09 


.40 



.38 
1.16 

.60 

.10 


0.59 
.74 



ft. 29 




.67 


.48 




1906-7 





bO 








0.05 

bO 






0.26 
.03 
.10 
.90 











.67 



1.90 
.85 
.23 
.50 




1.22 
.02 
1.04 
1.58 
.50 


1.23 
3.94 


5.57 
4.85 
1.63 
4.94 

.72 
1.91 

.99 
2.37 


4.27 
3.27 
9.28 
2.63 
12. 15 
4.94 
2.96 
8.81 


3.42 
3.06 
5.83 
1.08 
2.35 
.35 
.20 
2. 87 


8.12 
1.13 
2.97 
2.86 
4.28 
2.73 
1.28 
1.05 


23.72 


1907-8 


14.58 


1908-9 


b21.14 


1909-10 


b 16. 36 


1910-11 


21.97 


1911-12 


13.65 


1912-13 


8.35 


1913-14 


20.35 






Mean 








.16 


.52 


1.19 


2.87 


6.04 


2. 40 ! 3 fin 


.69 


.41 


b . 31 


b 17. 64 











a Records of Southern Pacific Co. 

Alviso, Santa Clara County, a 
[Elevation 11.4 feet.] 



b Interpolated. 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total 

for 
season. 


1906 




















0.45 
.28 
.12 



6.39 
.50 

1.00 
.35 
.40 


0.70 
.20 
.37 




.34 
.51 
.62 
.24 


0.50 
.40 



b.23 
.02 
.10 
.59 


.15 




1906-7 





bO 



.07 






'^0 

I 


.03 


0.20 


.07 
1.02 



.58 




.30 


.25 
.07 
.94 






0.90 
.10 

1.23 

1.50 
.25 
.26 
.72 

3.13 


5.51 
3.42 
1.66 
4.03 

.95 
1.90 

.50 
1.52 


3.87 
1.71 
7.75 
4.18 
11.28 
1.47 
2.47 
6.60 


2.45 
2.49 
5.95 
1.00 
3.11 
.33 
.18 
3.40 


7.32 

.97 

2.39 

63.32 

4.88 

2.47 

1.35 

.90 


20 95 


1907-8 


8.98 


1908-9 


6 20 28 


1909-10. 


6 15 71 


1910-11 

1911-12 


21.48 
9.47 
6.77 

16.44 


1912-13. . 


1913-14 




Mean 


.01 





.23 


.17 


1.01 


2.44 


4.92 


2.36 


2.95 


39 i ^s 


.22 


15.01 









a Records of Southern Pacific Co. 



b Interpolated. 



ISr^ CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES^ 1914. 

Records of precipitation in or near the Alameda Creek drainage basin {in inches) — Contd. 

Calaveras. Alameda County, a 
. [Elevation 600 feet.] 



Season. 



1874-75. . 
1875-76. . 
1876-77. . 
1877-78. . 
1878-79. . 
1879-80. . 
1880-81.. 
1881-82. . 
1882-83.. 
1883-84. . 
1884-85. . 
1885-86. . 
1888-89. . 
1889-90. . 
1890-91 . . 
1891-92. . 
1892-93.. 
1893-94. . 
1894-95. . 
1895-96. . 
1896-97. . 
1897-98. . 
1898-99. . 
1899-1900 
1900-1901 
1901-2... 
1902-3... 
1903-4. . . 
1904-5... 
1905-6. . . 
1906-7. . . 
1907-8. . . 
1910-11.. 
1911-12. . 



























Total 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


for 
season. 











4.10 


4.57 


0.18 


5.69 


0.59 


1.15 











16.28 











.35 


11.05 


4.82 


6.82 


6.80 


8.55 


1.75 


.36 





40. 50 











2.83 


.15 





6.50 


.67 


1.38 


.62 








12.15 











.28 


1.23 


2.39 


10.24 


14.88 














29.02 








.25 


.72 


.37 


.43 


4.66 


3.04 


5.79 


3.54 


2.48 


.15 


21.43 











1.35 


2.99 


5.33 


3.41 


3.00 


2.30 


8.24 


1.07 





27.69 











.04 


.69 


10.64 


4.60 


4.90 


2.22 


1.35 


.05 


.54 


25.03 








.21 


.43 


1.83 


3.60 


2.34 


2.91 


7. 06 


3.48 


.45 


.01 


22.32 








.46 


1.88 


2.19 


2.81 


1.17 


1.94 


4.33 


3.16 


3.46 





21.40 








.33 


1.73 


.84 


1.13 


5.51 


9.81 


9.30 


6.87 


.39 


1.35 


37.26 





.10 


.25 


1.80 


.02 


11.98 


2.91 


.29 


.47 


1.47 


.05 


.29 


19.63 








.10 





10.95 


2.67 


8.11 


1.37 


2.02 


6.35 








31.66 








.50 





4.17 


3.32 


.64 


1.07 


6.63 


1.06 


2. 48 ! 


19.87 











5.61 


3.99 


12.88 


10.02 


5.73 


3.46 


2.10 


1.75 





45.54 








.75 





.10 


4.91 


.90 


6.24 


3.29 


2.89 


.90 


.25 


20.23 








.50 


.30 


.75 


10.29 


.99 


2.19 


5.01 


1.81 


3.20 


.20 


25. 24 











1.75 


8.39 


7.08 


5.71 


3.86 


8.35 


3.15 


.91 





39.20 








.15 


.30 


2.72 


3. 59 


8.12 


9.64 


2. 63 


1.05 


2.04 


.57 


30.81 








1.83 


3.27 


1.00 


12.02 


9.13 


4.02 


3.00 


2.75 


1.61 





38.63 








.31 


.87 


2.36 


2.66 


8.41 


.52 


2.14 


6. 53 


1.72 





25.82 





.55 


.30 


2.02 


4.97 


4.47 


2.64 


7.61 


7.47 


.90 





.27 


31.20 





.05 





1.51 


1.11 


2.45 


1.64 


3.31 


.91 


.50 


1.67 


.27 


13.37 








.61 


1.32 


l.OS 


2.16 


4.53 





9.83 


1.28 


1.17 





21.98 











5.68 


5.04 


3.50 


3.35 


1.45 


2.83 


2.80 


1.19 





25.84 











4.16 


7.11 


2.15 


4.19 


6.69 


1.88 


2.76 


1.72 





30. 66 








.80 


1.75 


2.01 


1.67 


1.58 


7.24 


5.25 


1.95 


1.02 





23.27 











1.80 


4.25 


1.79 


6.15 


2.09 


7.60 


.85 


.42 





24.95 











.18 


5.18 


1.31 


1.73 


7.94 


6.89 


4.01 


.25 





27.49 





.62 


3.27 


2.41 


1.73 


3.23 


3.20 


3.78 


5.68 


1.47 


3.33 





28.72 














2.88 


1.95 


8.64 


3.90 


6.77 


1.52 


1.61 


.77 


28.04 








.33 





1.16 


8.60 


5.48 


2.13 


14.41 


.24 


.01 


.26 


32.98 











.86 


.12 


6.40 


3.10 


3.54 


1.13 


.26 


1.93 





17.34 











.50 


.38 


.96 


14.94 


3.71 


6. 01 


.96 


.62 


.04 


28.12 








.01 


1.26 


1.01 


3.03 


2.41 


.39 


3.12 


2.02 


.82 


.72 


14.79 





.04 


.32 


1.50 


2.89 


4.31 


4.98 


4.04 


4.68 


2.34 


1.14 


.17 


26.41 



a The future water supply of San Francisco from the conservation and use of its present resources, p. 449. 
Oct. 31, 1512. 



GROUND-WATER RESOURCES OF NILES CONE, CAL. 137 

Records of precipitation in or near the Alameda Creel: drainage basin {in inches) — Contd. 
Lick Observatory, Santa Clara County.a 

[Elevation 4,209 feet.] 





























Total 


Season. 


July. 


Aug. 


Sept. 


Oct. 


^Jov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


for 
season. 


1881 














3.51 
3.55 
3.10 
5.60 


5.99 
2.90 
3.75 
12.76 


1.13 
5.40 
8.66 
16.35 


0.98 
4..70 
2.66 
1.24 


0.09 

.48 

7.55 

3.85 


0.33 
1.06 

3.85 




1881-82 












0.10 

.65 


0.33 
6.16 
2.15 


0.91 
3.45 
1.48 


9.72 
1.93 
2.05 


29.15 


1882-83.. . 


37.26 


1883-84 


58.09 


1884-85 





.15 


.65 


3.71 


.01 


33.84 


1.99 


.57 


1.15 


2.08 


.16 


.36 


44.67 


1885-86 








.15 


.05 


1.92 


9.80 


4.44 


1.80 


5.77 


6.79 


.70 





31.42 


1886-87 











.60 


2.82 


2.34 


2.83 


7.80 


1.39 


5.75 


.25 


0.30 


24.08 


1887-88 


.04 




.02 


.33 
.49 


.09 
.03 


0.90 
3.27 


11.25 
4.23 


10.04 
1.04 


1.38 
1.42 


3.40 
6.17 


,.68 
1.92 


1.25 
3.21 


0.67 
0.05 


30 03 


1888-89 


21.85 


1889-90 











4.38 


4.46 


13.19 


7.93 


6.60 


4.39 


1.79 


2.42 





45.16 


1890-91 








.80 


.02 


.58 


5.39 


1.38 


7.12 


4.10 


3.08 


1.01 


0.57 


24.05 


1891-92 








.28 


.61 


.38 


9.54 


1.97 


2.99 


5.98 


1.90 


3.52 


.32 


27.49 


1892-93 





Tr. 


.24 


1.38 


10.30 


5.56 


3.29 


3.45 


8.99 


3.61 


.95 


.16 


37.93 


1893-94 








.48 


.66 


4.01 


3.58 


9.74 


10.52 


2.54 


.89 


2.78 


0.64 


35.84 


1894-95 


.02 


Tr. 


1.64 


2.98 


.84 


11.90 


10.00 


3.08 


1.46 


2.30 


2.39 





36.61 


1895-96 


.01 





.08 


.78 


2.46 


3.16 


9.54 


1.08 


3.83 


6.70 


2.10 


.02 


29.76 


1896-97 


Tr. 


.28 


.47 


1.85 


5.86 


4.91 


3.50 


7.42 


6.45 


.82 


.28 


.38 


32.22 


1897-98 








.07 


1.25 


1.51 


2.70 


2.30 


4.16 


2.04 


.84 


2.41 


.38 


17.66 


1898-99 








.29 


1.33 


1.23 


2.13 


5.G3 


.75 


11.11 


1.40 


1.47 


.39 


25.73 


1899-1900 





.12 


Tr. 


6.37 


4.92 


4.16 


3.26 


1.70 


3.37 


4.06 


1.35 


Tr. 


29.31 


1900-1901 


.01 


.02 


.08 


3.48 


7.76 


2.21 


5.76 


5.92 


1.98 


3.33 


1.07 


.02 


31.64 


1901-2 





.05 


1.08 


2.19 


2.89 


1.61 


1.44 


9.42 


5.19 


2.61 


1.14 





27.62 


1902-3 











2.05 


3.01 


3.11 


8.86 


2.20 


9.89 


1.12 


.05 


Tr. 


30.29 


1903-4 








Tr. 


.29 


7.67 


1.39 


1.98 


9.53 


8.06 


4.28 


.45 


.03 


33.78 


1904-5 


Tr. 


.05 


2.33 


2.51 


2.05 


3.84 


4.04 


4.19 


5.91 


1.36 


2.27 





28.55 


1905-6 








.02 





3.00 


2.04 


11.66 


5.76 


9.82 


1.83 


3. 15 


1.15 


38.43 


1906-7 





Tr. 


.28 


.05 


1.92 


10.31 


9.74 


4.76 


13.80 


1.14 


.42 


.92 


43.34 


1907-8 


Tr. • 









.01 




1.62 



1.77 


.18 
2.63 
2.59 


7.77 
2.96 
6.87 


5.02 
18.18 
7.29 


4.26 
9.49 
3.12 


1.95 
4.05 
3.28 


.70 

.91 


2.39 
.11 
.12 


.02 

.07 


23 92 


1908-9 


37 42 


1909-10 


26.02 


1910-11 


.Ot 





.25 


1.06 


.94 


1.77 


15. 76 


4.37 


7.00 


1.35 


.75 





33.29 


1911-12 











.46 


1.21 


3. 72 


4.44 


.50 


3.96 


2.70 


1.31 


.44 


18.24 


1912-13 








2.01 


.94 


2.34 


2.28 


5.42 


.48 


3.40 


.94 




.07 


17.88 


1913-14 


.06 


.10 








5.34 


6.05 


11.57 


5.24 


2.31 


2.01 


1.80 


1.13 


35.61 


Mean 


.01 


.02 


.39 


1.55 


2.87 


5. 96 6. 05 


4.60 


5.42 


2.63 


1.53 


0.39 


31.42 











a Records of U. S. Weather Bureau. 



138 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1914. 

Records of precipitation in or near the Alameda Crceh drainage basin {in inches) — Contd. 

Livermorc, Alameda County.a 

[Elevation 485 feet.] 



Season. 



1871... 
1871-72. 
1872-73. 
1873-74. 
1874-75. 
1875-76. 
1876-77. 
1877-78. 
1878-79. 
1879-80. 
1880-81. 
1881-82. 
1882-83. 
1883-84. 
1881-85. 
1885-86. 
1886-87. 
1887-88. 
1888-89. 
1889-yO. 
18y0-91 . 
1891-92. 
1892-93. 
1893-91. 
1894-95. 
1895-96. 
1896-97. 



1898-99... 
1899-1900. 
1900-1901 . 
1901-2.... 
1902-3... 
1903-4.... 
1904-5.... 
1905-6..., 
1906-7..., 
1907-8.... 
1908-9.... 
1909-10... 
1910-11... 
1911-12... 
1912-13... 
1913-14... 



Mean 



July. 



















.40 
















Tr. 


Tr. 


Tr. 


Tr. 


Tr. 
Tr. 
Tr. 

.27 



.02 



Aug. 





Tr. 























.10 












.73 








,02 



03 



Sept. 








.30 













Tr. 

.34 

.35 

.30 

.05 



.80 
.76 



1.62 

Tr. 
.20 

Tr. 
.03 
.62 
.10 

Tr. 
.48 

Tr. 



Oct. 



Tr. 


.42 

1.67 



1.26 

1.27 
.24 
.83 


.08 

1.52 

1.52 

1.14 


.30 





3.94 


.05 

1.65 



1.15 
.83 

1.48 

1.43 
.74 

2.52 

1.93 
.70 
.47 
Tr. 

1.00 


.03 
.81 
.27 
.75 
.29 
.43 
.71 



.30 



Nov 



1.13 
1.22 

.70 
2.03 
7.23 

.10 
1.29 

.31 
1.06 

.65 

.78 
1.48 

.57 

.02 
6.20 

.70 

.61 
3.80 
2.95 


.38 
4.97 
1.59 

.50 



I 1- 



02 

.52 

.25 

2.49 

4.48 

1.90 

2.07 

2.16 

.78 

1.61 

1.34 

.04 

.60 

1.68 

.10 

.29 



2.47 



1.61 



Dec. 



1 1. 69 

3.87 

4.48 

.20 

1.62 



.73 

.17 

1.94 

7.75 

1.97 

.38 

.44 

6.22 

1.94 

.81 

3.51 

2.21 

8.63 

3.31 

4.42 

7.27 

2.14 

8.56 

1.28 

1.71 

1.31 

1.61 

2.07 

1.06 

.74 

.87 

.59 

1.42 

1.18 

6.45 

3.90 

1.55 

5.77 

1.32 

1.71 

.81 

3.17 



Jan. 



1.42 
2.15 
1.04 
2. 90 
5.40 
2. 68 
2.47 
4.61 
2.83 
1.48 
2.40 
1.07 
2.38 
4.03 
1.72 
4.20 
.90 
3.20 
.46 
5.24 
.54 
.84 
3.02 
4.97 
6.83 
7.16 
1.89 
1.47 
2.00 
2.44 
2.69 

^^3.99 

3.19 

.89 

2.43 

15.56 
3.07 
2.27 

10.18 
2.50 

12.60 
2.66 



7.10 



Feb. 



1.93 

2.69 

3.73 

1.03 

1.20 

3.01 

.56 

6.73 

1.78 

1.80 

2.62 

1.72 

.63 

5.29 

.36 

.24 

6.23 

.94 

.07 

3.71 

4.18 

1.08 

3.12 

5.36 

1.56 

.17 

3.54 

1.78 

.08 

.34 

5.15 

3.52 

.94 

4.18 

2.30 

2.67 

1.86 

1.35 

3.96 

1.14 

1.42 

.20 

.38 

2.11 



Mar. 



3.34 I 2.26 



0.36 

.65 

.68 
1.34 

.35 
4.39 
1.10 
2.01 
2.49 
1.45 
1.06 
4.85 
3.45 
5.92 

.78 
1.18 

.23 
2.51 
5. 15 
2.85 
2.50 
3.96 
3.68 

.81 
1.81 
1.50 
4.01 

.78 
4.81 
1.11 

.95 
2.69 
5.65 
3.71 
3.12 
5.18 
8.85 

.:5 

1.94 
1.90 
4.45 
1.99 
1.65 



2.53 



Apr. 



1.25 

.43 

.15 

.95 



.73 

.13 

.96 

.75 

6.51 

1.93 

1.03 

1.50 

2.70 

1.29 

2.36 

1.60 

.60 

.51 

.86 



.90 

1.40 

.58 

1.26 

3.11 

.24 

.45 

.35 

.86 

1.80 

.75 

.81 

1.56 

.93 

.95 

.47 

.28 



.10 

.69 

.73 

.54 

.76 



May. June. 



0.02 




.32 


.33 
.39 
.06 

1.34 
.91 


.20 

2.18 
.20 
.08 




.66 

2.25 
.48 
.40 

1.30 
.73 

1.91 

1.25 
.39 


.96 
.15 

1.10 

1.58 
.32 
.12 
.24 



1.61 
.16 
.53 

Tr. 

Tr. 
.24 
.94 
.58 
.45 



.58 



32 








.20 


.04 





1.73 






.30 
Tr. 


.15 
Tr. 


.52 




.08 
.35 
.22 









Tr. 


.56 
.56 

Tr. 
.05 
.04 
.07 
.65 



Total 
for 



19.06 
10.69 
12.26 
11.67 
19.99 

6.01 
17.66 
10.11 
15.98 
16.45 
11.70 
13.86 
22.75 
12. 01 
16.17 
11.17 
13.13 
15.81 
28. 66 
14.16 
14.25 
26.29 
17.16 
24.-37 
16.35 
17.28 

9.11 
11.54 
12.93 
19.82 
12.48 
14.25 
13.33 
15.81 
19.32 
22.99 

9.93 
18.58 
14.50 
21.28 

9.60 

5.15 
17.01 



15. 



a Records of U. S. Weather Bureau. 



b Interpolated. 



GEOUND-WATER RESOURCES OF NILES CONE, CAL. 



139 



Records of 'precipitation in or near the Alameda Creek drainage basin (in inches) — Contd 

Niles, Alameda County.n 

[Elevation 87 feet.] 



July. 



Aug. 



Sept. 



Oct. 



Nov. 



Dec. 



fan. 



Feb. 



Mar. 



Apr. 



May. 



June. 



Total 
for 



1870-71. 
1871-72. 
1872-73. 
1873-74. 
1874-75- 
1875-76. 
1876-77. 
1877-78- 
1878-79. 
1879-80. 
1880-81- 
1881-82. 
1882-83. 
1883-84 . 
1884-85- 
188.5-86- 
1886-87- 



1889-90.. 
1890-91 . - 
1891-92.. 
1892-93.. 
1893-94.. 
1894-95.. 
1895-96.. 
1896-97-- 
1897-98-- 
1898-99-- 
1899-1900. 
1900-1901 . 
1901-2... 
1902-3... 
1903-4... 
1904-5... 
1905-6... 
190()-7... 
1907-8--. 
1908-9... 
1909-10. . 
1910-11-- 
1911-12.- 
1912-13-- 
1913-14-- 



















Tr. 

.01 





.03 


Tr. 

Tr. 

.10 


Tr. 

Tr. 

Tr. 












.08 





Tr. 
















Tr. 








.83 



.09 


.03 


Tr. 

.48 

Tr. 

Tr. 









.07 



.44 
.71 
.34 




.51 
.39 


.45 
.21 
.01 
.14 

1.42 
.75 
.57 

Tr. 

1.46 


.02 
.32 





2.80 
.02 
.31 




.66 











0.05 
.11 
.66 

2.44 
.10 

2.75 
.23 
.71 
.67 


.38 

1.29 

1.47 

1.30 
.35 
.64 
Tr. 
.07 

4.30 


.06 

1.53 
.23 

1.49 
.72 

1.22 

2.42 

1.33 

4.24 

2.02 
.89 

1.06 
.13 

2.25 
Tr. 
.10 

1.40 
.55 

1.08 



1.11 
.28 
.02 



1.56 
2.00 

.55 
4.33 
8.83 

.15 
1.16 

.43 
1.57 

.63 

.87 
2.30 

.88 


8.78 
1.29 

.84 
3.87 
3.44 



6.16 

.92 

.68 

3.30 

4.67 

1.78 

2.49 

3.52 

1.45 

2.36 

1.97 

.03 

1.18 

1.86 

.14 

.38 

1.04 

2.97 



2.04 
11.91 
5.00 
4.00 


3.52 


1.96 
.34 
3.41 
9.03 
2.59 
.81 
1.21 
5.75 
1.92 
1.14 
3.25 
3.53 
12.13 
3.05 
6.45 
5.28 
2.69 
9.45 
1.36 
2.91 
1.95 
1.65 
2.91 
1.65 
1.19 
1.46 
.78 
2.13 
2.16 
0.80 
4.42 
1.66 
5.01 
.91 
2.47 
1.56 
4.19 



2.00 
2.15 
1.07 
3.53 
3.44 
4.36 
3.03 
7.67 
3.10 
1.94 
4.36 
1.52 
1.44 
3.78 
1.58 
5.63 
1.07 
3.99 

.55 
7.18 

.65 
1.12 
2.65 
7.28 
6.81 
7.45 
2.08 
1.71 
2.78 
3.49 
3.31 
1.48 
4.26 
1.33 
3.43 
5.27 
4.74 
2.97 
9.00 
4.44 
13.31 
2.15 
3.44 



2.12 

4.32 

5.15 

.82 

.23 

4.12 

.67 

8.50 

2.66 

1.29 

3.08 

1.74 

.30 

6.18 

.15 

.73 

1.01 

1.80 

.42 

3.63 

4.72 

1.41 

2.73 

4.99 

2.55 

.30 

4.47 

2.20 

.49 

.87 

7.87 

5.80 

1.36 

5.56 

3.21 

4.48 

3.57 

2.57 

7.06 

2.26 

4.93 

.20 

.31 

2.94 



0.27 
1.30 

.66 
3.14 

.69 
3.40 
1.02 
3.58 
3.89 
l.CO 
1.06 
4.75 
2.77 
5.41 

.66 
1.67 
1.87 
3.07 
5.59 
3.03 
2.57 
3.71 
5.58 
1.23 
2.15 
1.66 
4.98 

.88 
6.09 



1, 
1, 
3. 
5. 
4 
3. 
5. 
10.09 



3.19 

2.55 

.85 

2.75 

1.68 

.68 



0.82 

.94 

.32 

1.40 



.85 

.42 

1.50 

2.09 

5.87 

1.53 

1.17 

1.46 

3.74 

.92 

4.19 

.14 

.15 

.95 

1.12 

2.23 

1.10 

1.67 

.54 

1.73 

4.47 

.56 

.39 

.26 

.91 

3.05 

1.31 

. 75 

2.11 

1.40 

1.33 

.77 

.23 



.47 

.44 

1.84 

.66 










.13 
.70 

1.03 
.07 

1.24 



.42 



48 



1.35 


.45 
2.99 

.18 


.25 

.14 

.78 
1.59 
1.08 
1.10 
1.96 

.47 
1.94 

.86 
1.07 

.16 
1.28 

.66 

.79 
1.26 
1.40 


.32 



71 
.71 
.21 



.37 
Tr. 


o' 

.01 
.07 
.40 
.01 


.06 
Tr. 
.02 
.43 




.29 
.24 
.49 
.08 






.08 
Tr. 
.92 













.32 



Mean 



Tr. 



,03 



.28 



97 



3. 36 3. 75 3. 00 



2.91 



1.37 



73 .19 



22.65 
14.31 
14.10 
11.81 
25.88 

9.34 
24.67 
14.54 
17.70 
20.06 
13.55 
13.80 
26.25 
10.60 
23.53 
14.85 
14.88 
16.97 
35.91 
14.83 
16.39 
23.46 
21.91 
27.30 
19.58 
14.02 
11.99 
15.89 
18.65 
24.87 
17.47 
17.17 
18.53 
23.47 
23.89 
28.35 
12.90 
22.64 
18.33 
20.58 
12.37 

9.68 
18.91 



18.61 



a 1870-71 to 1911-12, records of U. S. Weather Bureau; 1912-13 and 1913-14, records of Southern Pacific Co. 

Pleasanton, Alameda County.a 
[Elevation 355 feet.] 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


Jtme. 


Total 

for 
season. 


1906 




















0.20 
.42 
.20 


.33 
.80 

1.27 
.27 
.83 


1.59 
.07 
.30 

6.48 


.13 
.81 
.48 
1.9 


0.57 
.20 








.87 


.19 




1906-7 









.12 

.01 


















.25 
.65 









.11 




1.17 
.50 
.29 




.30 




1.90 



1.25 

1.63 
.60 
.28 
.67 

3.73 


7.57 
4.20 
1.26 
4.68 
1.41 
2.04 
1.32 
2.89 

3.17 


3.94 
2.80 

10.73 
4.44 

12.60 
1.54 
4.60 

14.94 

6.95 


1.29 

1.15 

4.51 

.65 

1.75 

.20 

.25 

2.18 


8.42 
1.25 
2.03 
2.29 
2.83 
2.56 
2.78 
.47 


23.81 
11.07 
6 21.11 
14.96 
19.98 
9.57 
10.67 
17.05 


1907-8 .. 


1908-9 


1909-10 


1910-11 


1911-12 


1912-13 


1913-14 




Mean 


.16 


1.27 


1.50 


2.83 


.39 


.46 


.20 


16.03 





a Records of Southern Pacific Co. 
70933°— 15 3 



Interpolated. 



140 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1914. 



Records of precipitation in or near the Alameda Creek drainage basin {in inches) — Contd. 

San Jose, Santa Clara County .a 

[Elevation 95 feet.] 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total 

for 
season. 


1874 














2.61 
2.75 
4.08 
2.23 
5.53 
1.48 
1.48 
2.12 
1.17 
1.06 
3.18 
1.83 
3.59 

.68 
3.06 

.50 
6.52 

.55 
1.11 
2.95 
4.73 
6.28 
5.17 
1.68 

.93 
1.88 
2.05 
3.98 

.81 
2.74 
1.28 
2.70 
2.86 
4.61 
2.63 
7.69 
2.31 
12.38 
1.36 
2.29 
6.23 


0.77 

.41 

3.41 

.48 
6.94 
3.18 
1.35 
2.04 
1.49 

.94 
3.68 

.18 
1.12 
6.81 
1.09 

.70 
3.64 
5.27 
1.60 
2.68 
2.61 
1.42 

.27 
3.43 
1.93 

.21 

.44 
5.47 
4.42 
1.27 
3.01 
2.65 
2.31 
1.88 
2.46 
4.87 

.83 
2.03 

.30 

.09 
3.94 


2.83 

.39 
3.11 

.78 
2.22 
5.85 

.96 

.80 
4.26 
2.70 
6.23 

.86 
1.89 

.63 
3.00 
5.80 
2.08 
2.47 
4.75 
5.12 

.69 
1.46 
2.22 
2.64 

.52 
4.17 
1.36 

.75 
2.65 
4.99 
2.73 
2.73 
4.47 
7.75 
1.14 
2.77 
2.84 
6.26 
2.80 
1.17 

.90 


0.87 
Tr. 
.41 


1.48 

1.24 

3.66 

1.28 

1.10 

.66 

3.38 

2.75 

4.47 

1.28 

.31 

.79 

.55 

1.79 

.65 

1.35 

.«3 

2.05 

2.79 

.91 

.20 

.48 

1.66 

2.37 

1.29 

.84 

1.74 

1.01 

.90 

.46 

.23 



.41 

.45 

1.95 

.38 

.65 


0.21 
Tr. 

.25 
.05 
.02 

1.58 
.67 


.55 

2.18 
.05 
.11 




.60 
.96 
.75 
.26 

1.60 
.30 

1.36 

1.36 
.44 
.16 
.44 
.65 
.96 
.82 
.88 


.26 

1.77 
.75 
.08 
.67 



Tr. 
.21 
.70 
.77 
.19 



.45 






.06 


.12 





2.15 
Tr. 




.22 
.04 


.05 
.05 


.40 





Tr. 
.06 
Tr. 
.01 
Tr. 








.43 
.42 
.01 
.05 
.02 
.07 
.46 
.01 
.25 




1874-75 





Tr. 










.03 

.02 









.01 




.02 







Tr. 





Tr. 


Tr. 

.09 

























.74 





Tr. 



.25 









.08 


0.10 


.11 


.48 




.02 
.04 
.09 
.08 




.61 
.60 


.05 
.37 





1.08 
.05 
.32 
.21 

1.13 


.17 
.44 





1.94 
Tr. 
.13 
.06 
.09 
.75 
.09 


.71 
Tr. 


1.81 
Tr. 

1.17 
.37 
.80 

.87 

%5 

.87 
.67 

1.50 
.06 
.49 
.03 



4.48 


.08 

1.00 



1.32 
.83 

1.03 

1.01 
.61 

3.26 
.62 

1.00 
.95 
.12 

1.43 


.01 
.98 
.19 
.72 
.20 
.80 
.21 
.02 


1.91 

6.10 

.01 

.85 

.76 

1.79 

.49 

.88 

1.32 

.28 

.06 

7.39 

.73 

.70 

3.88 

1.73 

.05 

.46 

4.00 

.81 

.55 

1.08 

2.82 

.37 

.45 

2.70 

4.36 

1.06 

2.18 

.99 

1.20 

2.17 

.98 

.13 

1.11 

1.27 

.28 

.18 

.29 

4.10 


0.08 
2.12 

1.87 

.97 
2.99 
5.60 
1.83 

.82 

.37 
3.90 
2.11 

.71 
2.53 
2.44 
10.55 
2.40 
5.84 
7. 77 
1.69 
7.80 

.84 
2.55 
1.20 

.44 
1.43 
1.32 

.43 

.92 

.34 
2.28 
1.23 
6.39 
3.65 
1.54 
5.37 

.68 
2.03 

.43 
3.00 


7.90 


1875-76 


19.47 


1876-77 


4.83 


1877-78 


19.28 


1878-79 


16.40 


Ig79_80 


13.77 


1880-81 


12.45 


1881-82 


11.75 


1882-83 


10.59 


1883-84 


20.08 


1884-85 


11.27 


1885-86 


20.63 


1886-87 


11.36 


1887-88 


12.17 


1888-89 


15.71 


1889-90 


30.30 


1890-91 


12.88 


1891-92 


16.51 


1892-93 


25. 17 


1893-94 


12.92 


1894-95 


23.32 


1895-96 . . . 


13.69 


1896-97 


16.56 


1897-98 . . 


6.87 


1898-99 


10.02 


1899-1900 . . . 


13.87 


1900-1901 


19.88 


1901-2 


12.98 


1902-3 


13.89 


1903-4 


10.47 


1904-5 


17.96 


1905-6 


15.12 


1906-7 


22.71 


1907-8 


11.69 


1908-9 


18.31 


1909-10 


14.52 


1910-11 


22.65 


1911-12. 


10.58 


1912-13 


6.35 


1913-14 


19.45 






Mean 


Tr. 


.03 


.24 


.76 


1.56 


2.51 


3.05 


2.28 


2.77 


.121 


.55 


.13 


15.09 



o Records of U. S. Weather Bureau. 



GEOUND-WATER KESOUECES OF NILES CONE, CAL. 



141 



Records of precipitation in or near the Alameda Creeh drainage basin (in inches) — Contd. 

Sunol, Alameda County .a 

[Elevation 227 feet.] 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total 

for 
season. 


1889 











.20 













.30 












0.67 
8.36 
3.78 
.77 
2.67 
6.64 
6.87 
7.17 
2.17 
1.78 
3.19 


0.35 
4.98 
1.06 
1.21 
2.79 
6.38 
2.73 

.32 
4.32 
2.38 

.31 


5.52 
3.63 
1.89 
3.87 
6.43 
1.32 
1.70 
1.10 
5.75 
.75 
6.72 


0.80 

1.21 

2.23 

1.12 

2.09 

.73 

1.66 

4.05 

.42 

.30 

.99 


2.75 

1.07 
.54 

1.81 
.24 

1.36 
.69 
.88 
.35 

1.04 
.56 

1.03 








.30 


.08 


.21 

.11 




1889_g0 




.90 
1.00 


.07 
1.45 

.37 

.46 


.80 


4.69 


.12 
1.80 

.18 
1.39 

.45 
1.33 
1.68 
1.11 


3.69 

.14 

.37 

6.35 

2.09 

.60 

2.00 

4.31 

.48 

.52 


11.36 
3.51 
6.27 
4.82 
2.65 
9.93 
1.17 
2.61 
1.89 
1.98 


38.99 


1890-91 


14 05 


1891-92 


16.54 


1892-93 


27.19 


1893-94 


21.72 


1894-95 


27.02 


1895-96 


17 59 


1896-97 


22.22 


1897-98 


10 51 


1898-99 


16.29 






Mean, 1889 to 1898- 
99 


.02 


.03 


.51 


1.28 


2.06 


4.62 


4.01 


2.44 


3.52 


1.42 


.06 


21.00 






1898_99 




















.17 





.32 









.83 



.93 



2.57 


.25 


.48 

.71 

2 


.86 
•3.90 

2.58 

1.31 
.76 
.06 

1.96 





1.43 
.38 
.89 
.68 
.90 


.83 
4.30 
5.21 
1.92 
2.67 
4.73 
1.22 
2.42 
1.69 


.84 
2.05 

.23 
1.10 


2.10 
4.30 
1.81 
2.10 
1.30 
.72 
2.28 
2.47 
7.44 
5.81 
2.39 
3.54 
1.38 
3.25 


3.40 
3.29 
2.97 
1.27 
4.88 
2.17 
2.70 
6.83 
4.44 
3.53 

11.72 
4.97 

14.83 
2.90 


.30 
1.33 
7.61 
5.^ 
1.51 
6.04 
3.48 
3.74 
3.18 
2.76 
6.03 
2.34 
3.26 

.41 


9.05 
2.10 
1.51 
4.23 
5.95 
5.88 
4.88 
6.91 
11.03 
1.32 
3.30 
3.72 
6.38 
3.23 


2.00 

2.12 

2.57 

1.28 

1.95 

2.20 

1.38 

1.65 

.55 

.31 



.49 

1.41 

1.90 


.83 
.76 

1.11 
.66 


.36 

2.50 
.52 
.70 

1.02 



1.24 


.21 







.67 

.50 





.88 


20.41 


1899-1900 


22 27 


1900-1901 


25.37 


1901-2 


19 54 


1902-3 


19.02 


1903-4 


22.16 


1904-5 


23.29 


1905-6 


25.21 


1906-7 . ... 


29 78 


1907-8 


16.18 


1908-9 


25 14 


1909-10 


18.53 


1910-11 


28.43 


1911-12 


15.81 






Mean, 1898-99 to 
1911-12 





.03 


.41 


1.12 


2.09 


2.92 


4.99 


3.42 


4.96 


1.41 


.71 


.16 


22.22 







a 1889 to 1898-99, records of Southern Pacific Co.; 1898-99 to 1911-12, records of Spring Valley Water Co. 
(The future water supply of San Francisco from the conservation and use of its present resources, p. 472, 
Oct. 31, 1912.) 



142 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1914. 



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143 



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2§ 






144 CONTEIBUTIONS TO HYDROLOGY OF UNITED STATES, 1914. 

GEOLOGIC FORMATIONS IN RELATION TO GROUND 

WATER. 

OUTLINE OF FORMATIONS. 

The Contra Costa and Mount Hamilton ranges are composed of 
strata of Jurassic or Lower Cretaceous and later age. They are of 
complex structure and have been greatly faulted. The major faults, 
as elsewhere in the Coast Ranges of Cahfornia, have a northwesterly 
trend. The older rocks in the mountains are of importance in con- 
nection with the present investigation only in so far as their elevation 
and topography influence precipitation and run-off, but the Quater- 
nary and some of the Tertiary deposits in the valleys are valuable 
water bearers. 

Geologic formations in the Alameda Creek drainage basin and adjacent areas. 



System. 


Series. 


Formation. 


Quaternary. 


Recent and Pleistocene. 


Alluvium. 


Tertiary or 


Quaternary. 




Santa Clara formation. 






Pliocene. 


Orinda formation. 


Tertiary. 


Miocene. 


Monterey group. 




Eocene. 


Tejon formation. 


Cretaceous. 


Upper Cretaceous. 


Chico formation. 


Lower Cretaceous. 


Knoxville formation. 


Jurassic (?). 


(?) 


Franciscan group. 



JTJRASSIC (?) SYSTEM. 

FRANCISCAN GROUP. 

The Franciscan group is characterized by sandstones, bedded radio- 
larian cherts, and jaspers, greenstones, glaucophane schist, and some 
other varieties of crystalHne schist. It is much shattered and broken, 
is traversed by many faults, and is cut by many intrusive rocks, 
chiefly of a basic character and now in part altered to serpentine. 
The group consists chiefly of sandstone, but the occurrence of the 
other rocks mentioned gives to the group as a whole a distinctive 
lithology. 

The Franciscan group occupies some 400 square miles of the Ala- 
meda Creek drainage basin and covers practically the whole of the 
basins of Arroyo Hondo, the upper Alameda, Arroyo del Valle, 
and Arroyo Mocho. In this large area there are a few small remnants 
of Cretaceous rocks, suggesting that Cretaceous formations may have 
covered the whole region at one time but have since been removed 
by erosion. Smaller outcrops of Franciscan rocks are found else- 
where in the Alameda Creek drainage basin. The Coyote and Little 
Coyote hills are composed wholly of rocks belonging to that group. 



GROUND- WATER RESOURCES OF NILES COKE, CAL. 145 

The age of the group has not been definitely determined but is 

certainly pre-Knoxville and by most geologists has been assigned to 

the Jurassic. 

CRETACEOUS SYSTEM. 

KNOXVILLE AND CHICO FORMATIONS. 

The Cretaceous system comprises locally two formations — the 
KjioxviUe, or Lower Cretaceous, and the Chico, or Upper Cretaceous. 
The Knoxville consists largely of shale, whereas the Chico is made 
up mostly of sandstone and shale with a conglomerate at its base.^ 
The Cretaceous formations occupy a continuous strip extending from 
a point in the hills east of Berkeley to a point just west and a httle 
south of the south end of Calaveras Valley. This strip is about 40 
miles long and ranges in width from less than a mile to more than 
6 miles at its widest point just north of Alameda Creek. By far the 
larger part is occupied by the Chico formation. Besides this large 
area of Cretaceous rocks there are a number of smaller outcrops. 

TERTIARY SYSTEM. 

EOCENE SERIES. 
TEJON FORMATION. 

The Eocene series is represented by a sandstone that belongs to 
the Tejon formation and outcrops over a small area in a syncline 
just west of the crest of Sunol Ridge. 

MIOCENE SERIES. 
MONTEREY GROITP. 

The Miocene series is represented by the Monterey group, which 
occupies a narrow strip that in most places borders the Cretaceous 
or the Franciscan rocks on the west, but varies in width and position 
with the structure. In this region the characteristic representative 
of the group is a sihceous shale much broken and shattered by earth 
movements and used extensively for road metal. 

A prominent formation in the Monterey group is the Briones sand- 
stone, which occupies a considerable area about the crest ^of the 
Monument Peak ridge and extends from the vicinity of Alameda 
Creek on the north to San Fefipe Valley on the south. It is charac- 
teristically a greenish mottled sandstone carrying abimdant marine 
fossils. 

PLIOCENE SERIES. 
ORINDA FORMATION. 

The Orinda formation ^ comprises the older part of the gravel, 
sand, and clay deposits in the mountain valleys of this region. It 
is of fresh-water origin and reaches a maximum thickness of more 

» Lawson, A. C, U. S. Geol. Survey Geol. Atlas, San Francisco folio (No. 193), 1914. 



146 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1914. 

than 4,000 feet.^ It occupies an area of about 50 square miles just 
south of Livermore Valley, and a much larger area north of the valley. 
As the Orinda formation is only partly indurated and comprises 
much porous material, it is of great importance as a water bearer. 
Both Branner and Lawson ^ regard the gravels of this formation as 
having an immense storage capacity. The catchment area of the 
Orinda formation tributary to the Livermore Valley, and hence 
ultimately to the Niles cone, covers more than 100 square miles and 
ranges from 500 or 600 feet to more than 1,200 feet above sea level. 
The formation no doubt acts as a high-level reservoir, feeding its 
water slowly into the lower parts of the valley and thus helping to 
maintain a higher water level in the more recent gravels that overlie 
the Orinda in the Livermore and Sunol valleys. 

TERTIARY OR QUATERNARY SYSTEM. 
SANTA CLARA FORMATION. 

The Santa Clara is a rather widespread formation of fresh-water 
origin extending at intervals along both sides of the Santa Clara 
Valley for almost its entire length. Within the area covered by this 
report it outcrops over 5 or 6 square miles in the low hills southeast 
of Irvington and southwest of Mission San Jose. These hills are 
composed entirely of shghtly indurated and poorly assorted sands, 
clays, and gravels belonging to this formation. The gravels, which 
are rather dirty, make up considerably less than a third of the forma- 
tion. The area of outcrop narrows toward the south and the forma- 
tion pinches out about half a mile south of the Alameda and Santa 
Clara county line.^ That this formation extends some distance into 
the valley both north and west of the hills near Irvington is indicated 
by the logs of wells in this vicinity and by the low yield of these wells. 
The age of the Santa Clara formation is still in question. 

QUATERNARY SYSTEM. 

PLEISTOCENE AND RECENT SERIES. 
ALLUVIUM UNDERLYING THE INTERIOR VALLEYS. 

The upper part of the fill in the Livermore and other interior 
valleys consists of alluvial deposits of the ordinary type. The water 
level in these deposits is a vital factor in the permanence of the flow 
of Alameda Creek and hence is an important element in the water 
supply of the Niles cone. The ground water in the Livermore and 
Sunol valleys, when not artificially lowered, rises as it approaches 

1 Branner, J. C, The future water supply of San Francisco from the conservation and use of Its present 
resources, p. 216, Oct. 31, 1912. 
2 Branner, J. C, idem pp. 207, 216; Lawson, A. C, idem, p. 230. 
3The writer is indebted to Mr. Harold Hannibal for the outlines of this formation. 



GROUND- WATER RESOURCES OF NILES CONE, CAL. 147 

the rock wall at the entrance of Niles Canyon and thus assists in 
giving permanence to the flow of the stream. The Livermore Valley 
is about 350 feet above sea level at its lower end and about 650 feet 
at its upper end. This gives a slope of about 300 feet in a distance 
of about 12 miles, or 25 feet to the mile. The water table has a slope 
that is somewhat more gentle but still sufficient to give the ground 
water an active mo\7ement toward the lower end and to cause it to 
rise to the surface in that vicinity wherever it finds an opening or 
wherever the earth is sufficiently porous. This rising water accounts 
for the swampy lands near Pleasanton. 

ALLUVIUM UNDERLYING SANTA CLARA VALLEY. 

Santa Clara Valley is covered to a considerable though unknown 
depth by alluvium. The Niles cone proper and the additional area 
covered by this report are occupied by this material. The thickness 
of the alluvium has not been determined, as none of the borings have 
reached bedrock except in the vicinity of the Coyote Hills, where 
four or five wells penetrate to solid rock. According to the driller's 
record, a well on the south bank of Alameda Creek about half a mile 
east of the upper bridge at Alvarado reaches bedrock at a depth of 266 
feet, but this record is probably erroneous, as none of the many other 
wells in this vicinity are reported to reach bedrock. One well at a 
distance of about half a mile is 416 feet deep, and another less than 
a mile away is 528 feet deep and struck good water-bearing gravel 
at the bottom. All these wells are owned by the Alameda vSugar Co. 

Alluvium lies beneath the salt marsh a,nd under the bay itself, as is 
shown by records of drill holes both on the marsh and in the bay. 
The fact that gravels are found below the bay is conclusive evidence 
that the region has sunk with reference to sea level. Some of these 
gravels are found at depths of more than 400 feet below the surface 
of the bay. That there has been recent sinking is further shown by 
the fact that present stream channels may be traced into the bay. 
The channel of Coyote Creek is distinctly traceable beneath the bay 
as far north as San Mateo, a distance of about 20 miles from its pres- 
ent mouth. Some of the streams now flowing into the sides of the 
bay also have well-defined channels extending beneath the bay to the 
submerged channel of Coyote Creek. (See fig. 9.) 

The alluvial deposits were made by streams with very irregular 
flow, at times subjected to enormous floods and at times carrying 
little or no water. The sediments were all brought down from the 
highlands on the east and represent the materials that once occupied 
the positions of the present mountain canyons. 

The mountainous topography of the Alameda Creek drainage 
basin, its paucity of timber and brush, the seasonal distribution of its 



148 CONTEIBUTIONS TO HYDKOLOGY OF UNITED STATES, 1914. 

rainfall, and the concentration of its run-off into a narrow outlet all 
contribute to make the creek most erratic, and the large extent of 
this basin gives volume to the floods. 

Because of the great floods to which the basin has been subjected 
and the large amount of water relative to the load of rock waste to 
be transported, the coarse materials have at times been carried far 
beyond the mouth of the canyon. This accounts for the abundance 
of gravels in well sections, even near the bay. These gravels are not 
in continuous sheets (see Pis. XIV to XVII), nor would this be 
expected from their mode of origin. They occur in lenses and string- 
ers, which are so abundant that the prospective well owner is almost 
sure to strike one or more of these beds at no very great depth. 
Many of the wells are only 50 or 60 feet deep, and wells more than 
100 feet deep are rather exceptional. 

Streams flowing over alluvial fans are continually changing their 
courses. They may be slowly eating away their banks on one side 
while building up on the other, and at the same time they may be 
depositing gravel in their channels. During later floods these gravels 
will be buried under finer sediments, thus forming broad lenses or 
sheets of gravel. At other times these streams break over their 
banks and may form altogether new channels, the old ones being 
buried beneath later sediments, thus giving rise to stringer-like 
deposits. 

The Santa Clara Valley is a region of aggradation. At the same 
time that the stream channels are formed their bottoms are brought 
to successively higher and higher levels by the deposition of gravel. 
In times of flood, when the water spreads over a large part of the 
Niles cone, natural levees are built, and the streams acquire an 
unstable position, resulting in frequent shifting. Thus hundreds of 
channels have been born and buried during the upbuilding of the 
cone. 

The old channels diverge from the mouth of the canyons, and, as 
this is a region of aggradation, one system is superimposed upon 
another until there is a complex ramification of old channels diverg- 
ing both horizontally and vertically somewhat like the roots of a 
tree. These old channels are buried and sealed in deposits of more 
or less impervious clay, and hence the water that is fed into them 
from the mass of gravel near the apex of the cone is under pressure in 
the lower and outer parts of the cone. This pressure gives rise to arte- 
sian conditions on the lower parts of the cone and in some places is 
sufficient to bring the water to the surface and produce flowing wells. 

Conditions similar to those of the Niles cone are found over aU 
parts of the Santa Clara VaUey, the vaUey fill having been deposited 
in a series of coalescent cones or fans. The percentages of the differ- 



ist Page(s): 









Sand Gravel 



iMile 



-200 



•300 



-400 



. GEOLOGICAL 



WATER-SUPPLY PAPER 345 PLATE X 




WELL SECTIONS ALONG LINE 0-P, PLATE 



WATER-SUPPLY PAPER 345 PLATE XV 



Feet 



125 



Sea level 



S=5 



LEGEND 



Adobe 



Clay 



Sand 



131 






OO 

'o 



Gravel 



-100 



\ 




WELL SECTIONS ALONG LINE Q-R PLATE X. 



\ 




WELL SECTIONS ALONG LINE S-T, PLATE X. 



13.72. 



S3 



I 



WATER-SUPPLY PAPER 345 PLATE XVII 

-87 88 ' ^^* 



190 



V 



.to°b;i°ji 



Gravel 



iMile 



-100 



•200 



. S. GEOLOGICAL SURVEY 



WATER-SUPPLY PAPER 346 PLATE XVII 




Sana Gravel 



WELL SECTIONS ALONG LINE U-V, PLATE 



GROUND-WATER RESOURCES OF NILES CONE^ CAL. 149 

ent materials of which the Niles cone and vicinity are composed have 
been computed from a study of 300 to 400 well logs, with the follow- 
ing result, which is believed to be reasonably accurate : 

Estimated composition of the valley fill underlying the Niles cone and adjacent tracts. 

Per cent. 

Clay 56 

Sand 14 

Gravel 30 

100 
ORIGIN OF GROUND WATER. 

GENERAL SOURCE. 

The ground water in the vicinity of Niles has the same source as the 
surface waters — that is, it originates in the rain that falls upon the 
drainage basins tributary to this part of the valley and, to a small 
ex teat, in the rain that falls upon the valley itself. The question is 
frequently asked by residents of the district: ''Does not our water 
come from the Sierra?^' This question should be answered in the 
negative. None of the water of the Niles cone and adjacent valley 
tracts comes from the Sierra Nevada or from any other source outside 
of the drainage basias tributary to the area. 

INFLUENCE OF THE NILES-IRVINGTON FAULT. 

The specific parts of the valley area that are supplied, respectively, 
by Alameda Creek and by the smaller streams are determined largely 
by the position of the Niles-Irvington fault. In general the struc- 
tural and physiographic features of the Coast Ranges of California 
are controlled by a great system of parallel faults having a northwest- 
southeast trend. The Niles-Irvington fault is one of these faults or 
a branch of one. Between Niles and Irvington it crosses a reentrant 
of the valley, cutting off the apex of the Niles cone and the flat land 
between Niles and Mission San Jose. It is plainly marked in its 
course across the valley land by an eastward-facing escarpment some- 
what more than a mile from the base of the mountains. (See PI. X 
and PI. XI, B.) This escarpment is in the valley fill of loose mate- 
rials and is therefore geologically very young — in fact, it is still grow- 
ing. Mr. J. C. Shinn reports that during the severe earthquake of 
1868 his father's house, standing directly on the fault line, was torn 
in two and the eastern part dropped about a foot below the western 
part. 

This fault has a profound local effect on the circulation of the 
ground water as weU as on the surface drainage referred to on page 132 
of this report. As a result of the displacement the buried gravel 
channels have apparently been blocked by the impervious materials 



150 CONTRIBUTIONS TO HYDEOLOGY OF UNITED STATES^ 1914. 



of the valley fill. Consequently the fault plane acts as an under- 
ground dam and prevents the passage of the ground water, except 
in small amounts, from the east side of that plane to the west side. 
The area between the fault scarp and the base of the mountains 
receives ground water from all the streams that discharge upon this 



Feet 
50= 



Fo- 



A 






Sea level 



:^ Feb. 18 
Jan. 18 



Jan. 4 
•^ Dec. 27 
Dec. 15 



91 106 111 112 113114 150 147146 141 144 

Figure 12.— Profiles of water table along line F-G, Plate X. 

area, but the area west of the fault receives very little ground water 
except from Alameda Creek, which is the only stream that drains 
across the fault in the area under discussion. Where the fault 
cuts through the large gravel deposits near the apex of the Niles 
cone it is probably less effective as a dam than where the pro- 



Feet 






















\ 


- 


30: 

20: 


■■\.. 


:l 


10^ 


Datum pla 


ne^ 


\ 


F o: 


-- 





- — 


- — 







. — '-^' 


[ 



Feb. 18 
Jan. 18 

Jan. 4 
Dec. 27 

Dec. 15 



91 106 111 112 113114 150 147146 141 144- 

Figure 13.— Graph showing fluctuation of water table along line F-G, Plate X. 

portion of fine sediments is greater, and some of the ground water 
derived from Alameda Creek may therefore cross the fault through 
underground channels. Even on the Niles cone, however, the ground 
water is greatly impounded by the fault, as shown by a difference of 
more than 20 feet in elevation of the water table at the J. C. Shum 
wells. (See table, p. 153.) 



GEOUN-D-WATER EESOURCES OF NILES CONE^ CAL. 



151 



WATER-LEVEL DATA. 

That the Niles-Irvington fault acts as an underground dam sub- 
stantially preventing the ground water east of the fault plane from 
crossing to the region west of this plane is proved by the abrupt 
change in the water table, as shown by the data given in the follow- 
ing tables. This abrupt change is brought out very clearly in the 
second table (p. 153), in which is given the depth to water in weUs 
arranged in pairs on opposite sides of the fault, and also in Plate X 
and in figures 12 to 24, inclusive. Figures 12 and 20 show profiles 
based on instrumentally determined levels; the other figures repre- 
sent fluctuations of the water table by means of graphs. In these 
graphs the position of the water table on the first date indi- 
cated is represented by horizontal lines except at the fault, where 
the actual differences in level are shown. Later positions of the 
water table are plotted relative to the horizontal lines. Where sec- 
tions DE, FG, and HE and concentric section C^ cross the fault Hne 
the relative elevations of wells on opposite sides were instrumentally 
determined;^ where the other sections, IJ and KL, cross the fault 
line the differences in elevation were determined by use of a hand 
level. The relation of the graphs to the profiles is shown by figures 
12 and 13, in which the same data for the section FG are plotted by 
the two methods. 



Joseph Furtado (133), 

Dec. 10, 1913 15.75 

Dec. 29, 1913 15.62 

Jan. 18, 1914 11.12 

Feb. 4, 1914 10.37 

Feb. 24, 1914 8.00 

County wei (132). 

Nov. 17, 1913 (dry). 50.00 
May 2, 1914 (dry). 50.00 

J. C. Shiiin (139). 

Dec. 2, 1913 30.00 

Dec. 12, 1913 29.83 

Dec. 23, 1913 25.25 

Dec. 28, 1913 19.42 

Jan. 2, 1914 17.67 

Jan. 8, 1914 17. 10 

Jan. 19, 1914 16.00 

Jan. 27, 1914 12. 21 

Feb. 5, 1914 16.54 



Depths, in feet, to the water table in the vicinity of Niles. 
[Numbers in parentheses correspond to those used on Plate X.] 

J. C. Shinn (147). 



Feb. 
Feb. 



Nov. 



17, 1914 17.71 

24, 1914 14.75 

J. C. Shinn (138). 

17, 1913 (dty)- 60.00 

J. C. Shinn (146). 



Nov. 20, 
Nov. 26, 
Dec. 13, 
Dec. 27, 
Dec. 29, 
Jan. 4, 
Jan. 8, 
Jan. 15, 
Jan. 22, 
Jan. 27, 
Feb. 5, 
Feb. 17, 
Feb. 24, 
Mar. 12, 



1913 32.43 

1913 32.43 

1913 32.63 

1913 22.70 

1913 22.00 

1914 19.02 

1914 19.25 

1914 17.96 

1914 16.22 

1914 13.80 

1914 15.66 

1914 16.33 

1914 13.66 

1914 15.25 



Nov. 20, 1913 51. 50 

Nov. 26, 1913 50.46 

Dec. 13, 1913 50.60 

Dec. 23, 1913 50.36 

Dec. 29, 1914 46.46 

Jan. 4, 1914 45.08 

Jan. 8, 1914 42.04 

Jan. 15, 1914 41.70 

Jan. 22, 1914 40.42 

Jan. 27, 1914 39.33 

Feb. 5, 1914 38.58 

Feb. 17, 1914 39.62 

Feb. 24, 1914 38.62 

Mar. 12, 1914 36.17 

H. J. Tilden (155). 

Nov. 7, 1913 28.34 

H. J. TUden (154). 

Nov. 17, 1913 (dry). 46.60 



1 The levels were run for the Spring VaUey Water Co. by J. H. Forbes and were kindly made available by 
the company. 



152 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1914. 



Depths, in feet, to the water table in the vicinity of Niles — Continued. 



County weU (153). 

Nov. 20, 1913 54.92 

Nov. 26, 1913 54.92 

Dec. 13, 1913 55.02 

Dec. 23, 1913 55.08 

Dec. 29, 1913 54.75 

Jan. 3, 1914 52.95 

Jan. 8, 1914 51.25 

Jan. 15, 1914 50.04 

Jan. 22, 1914 48.58 

Jan. 27, 1914 47.50 

Feb. 6, 1914 45.33 

Feb. 18, 1914 45.88 

M. J. Silva (156). 

Dec. 16, 1913 28.52 

Dec. 24, 1913 28.30 

Jan. 1, 1914 24.80 

Jan. 9, 1914 21.90 

Jan. 19, 1914 18.54 

Jan. 27, 1914 15.00 

Feb. 11, 1914 13.17 

Feb. 18, 1914 13.66 

Mar. 2, 1914 11.25 

Mar. 11, 1914 11.25 

M. G. Duarte (152). 

Nov. 1, 1913 57.50 

Nov. 13, 1913 56.00 

Nov. 30, 1913 56.00 

Dec. 12, 1913 56.25 

Dec. 24, 1913 54.00 

Dec. 31, 1913 50.92 

Jan. 13, 1914 48.33 

Jan. 19, 1914 47.00 

Jan. 28, 1914 46.00 

Feb. 1, 1914 46.50 

Mar. 3, 1914 47.00 

Mar. 11, 1914 42.33 

S. E. Stivers (157). 

Dec. 1, 1913 30.02 

Dec. 13, 1913 30.20 

Dec. 27, 1913 30.04 

Jan. 1, 1914 28.48 

Jan. 9, 1914 28.04 

Jan. 19, 1914 24.27 

Jan. 27, 1914 21.83 

Feb. 11, 1914 19.83 

Feb. 18, 1914 18.53 

S. E. Stivers (159). 

Dec. 1, 1913 20.38 

Dec. 27, 1913 19.96 



Jan. 1, 1914 18.25 

Jan. 9, 1914 15.62 

Jan. 19, 1914 12.00 

Jan. 27, 1914 8.58 

Feb. 11, 1914 5.60 

Feb. 18, 1914 5.36 

S. E. Stivers (160). 

Dec. 16, 1913 22.33 

Dec. 24, 1913 22.06 

Dec. 27, 1913 21.37 

Jan. 2, 1914 18.80 

Jan. 9, 1914 16.46 

Jan. 19, 1914 13.00 

Jan. 27, 1914 9.20 

Feb. 11, 1914 7.33 

Feb. 18, 1914 6.72 

Mar. 2, 1914 4.17 

Mar. 8, 1914 4.00 

S. E. Stivers (161). 

Dec. 16, 1913 59.17 

Dec. 27, 1913 59.64 

Jan. 2, 1914 58.90 

Jan. 9, 1914 58.17 

Jan. 19, 1914 57.12 

Jan. 27, 1914 55.90 

Feb. 11, 1914 55.53 

Feb. 18, 1914 54.43 

Mar. 2, 1914 51.40 

Mar. 8, 1914 50.50 

A. G. Peixoto (162). 

Nov. 7, 1913 54.77 

Dec. 1, 1913 56.00 

Dec. 27, 1913 55.20 

Jan. 2, 1914 55.00 

Jan. 12, 1914 54.50 

Jan. 21, 1914 53.75 

Jan. 27, 1914 53.12 

Jan. 31, 1914 52.70 

Feb. 5, 1914 51.92 

Feb. 24, 1914 50.00 

Mar. 4, 1914 50.00 

J. S. Leal (164). 

Dec. 27,1913 62.30 

Jan. 2, 1914 62.25 

Jan. 12, 1914 61.96 

Jan. 21, 1914 61.33 

Jan. 27, 19l4 60.83 

Jan. 31, 1914 60.50 

Feb. 5, 1914 59.92 

Feb. 24, 1914 58.00 



J. F. Nunes (172). 

Nov. 20, 1913 50.17 

Nov. 26, 1913 50.20 

Dec. 13, 1913 50.54 

Jan. 1, 1914 50.54 

Jan. 12, 1914 50.30 

Jan. 21, 1914 49.96 

Jan. 31, 1914 49.20 

Feb. 6, 1914 48.33 

Feb. 24, 1914 46.66 

California Nursery (165). 

Nov. 15, 1913 6.24 

Jan. 9, 1914 Flooded. 

Kirk (166). 

Nov. 7, 1913 34.29 

Jan. 28, 1914 22.00 

Feb. 10, 1914 21.00 

Mar. 2, 1914 19.00 

M. G. Peixoto (168). 

Nov. 7, 1913 64.69 

Dec. 4, 1913 67.00 

Dec. 15, 1913 66.66 

Dec. 22, 1913.. 68.00 

Dec. 27, 1913 67.33 

Dec. 29, 1913 68.00 

Jan. 1, 1914 67.50 

Jan. 5, 1914 68.00 

Jan. i2, 1914 67.83 

Jan. 26, 1914 65.50 

Feb. 4, 1914 66.00 

Feb. 16, 1914 66.00 

J. F. Brown (169). 

Dec. 27, 1913 73.42 

Jan. 1, 1914 72.46 

Jan. 9, 1914 71.55 

Jan. 19, 1914 69.70 

Jan.27,1914 67.44 

Jan. 31, 1914 66.62 

W. Hearsh (167). 

Dec. 13, 1913 56.56 

Dec. 27, 1913 56.10 

Jan. 1, 1914 55.46 

Jan. 9, 1914 54.93 

Jan. 19, 1914 53. 68 

Jan. 27, 1914 52. 00 

Jan. 31, 1914 51.38 



GROUND-WATER RESOURCES OF NILES CONE, CAL. 



153 



Depth to the water level in wells arranged in pairs on opposite sides of the Niles-Irvington 

fault. 

[The location of wells is shown on Plate X by corresponding numbers.] 



No. of 
well. 



132 
133 



138 
139 



147 
146 



154 
155 



161 



168 



Owner. 



Road well 

Joseph Furtado. 



J. C. Shinn. 
do 



H. J. Tilden. 
....do 



S. E. Stivers. 
do 



M. G. Peixoto. 
Kirk.... 



Side of 
fault. 



West. 
East. 



West. 
East. 



West. 
East. 



West. 
East. 



West. 
East. 



West. 
East. 



Depth of water 

level below 

surface. 



Feet. 

Dry at 50 
25.50 

Dry at 59. 80 
26.57 

53.81 
31.40 

Dry at 46. 60 
28.34 

58.58 
22.38 

64.19 
33.79 



Differ- 
ence in 
elevation 
of surface. 



Feet. 

} - 

} 2.31 

I aO 

I 4.29 

I a8 



Differ- 
ence in 
water 
level. 



Feet. 
23.50+ 

28. 23+ 

20.10 

18. 26+ 

31.91 

22.40 



Approxi- 
mate 

distance 
apart. 



Feet. 
100 

125 

150 

b500 

200 

300 



Date of 
measure- 
ment 
(1913). 



Nov. 17 

Do. 
Nov. 7 

Do. 
Nov. 15 

Do. 



a Approximate. 

b These weUs are both very near the fault line, the distance between them being chiefly along the fault. 

INTERPRETATION OF THE DATA. 

The data given in the preceding tables show that practically all 
the ground water on the west side of the Niles-Irvington fault, both 



Mar. 12 
Feb. 25 
Feb. 5 - 
Jan. 22 
Jan. 4 - 
Dec. 29 
Dec. 12 
A 



Feet 



10 



■OB 



147 153152 161 162 164 168 

Figure 14.— Graph showing fluctuation of water table along line A-B, Plate X. 

on the Niles cone and on the adjacent area to the south (PI. X), 
comes from Alameda Creek, the area east of the fault being supplied 



Jan. 27 q 
Mar. 12 
Feb. 15 
Jan. 15 



Feet 






Dec. 27 
Nov. 10 
Nov. 26 ^ 
A 



i>-. 



-^^=r 



Datum pTane 



\ 



10 



:0C 



146 155 156160 159 165166 167 

Figure 15.— Graph showing fluctuation of water table along line A-C, Plate X. 

in the north by Alameda Creek and farther south by the smaller 
streams that emerge from the mountains south of this creek. If 



154 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1914. 



wells on opposite sides of the fault receive water from the same 
source there should be no appreciable difference in the time in which 
they show response to rainfall, and whatever slight lag the wells 
on the west side might show should be as much in the northern as in 
the southern part of the area. If, however, as stated, the wells on the 

east side are fed not only by Alameda 
Creek but also by the small streams far- 
ther south, while the wells on the west 
side are supplied only from Alameda 
Creek, there should be considerable dif- 
ference south of the Niles cone in the 
time in which two wells just across 
the fault Une from each other respond 
to rainfall. Moreover, this difference 
in time of response should increase 
toward the south, because the ground 
water on the west side must travel 
successively longer and longer dis- 
tances on its journey southward. 
That this lag really occurs and that 
it is progressive southward is abun- 
dantly' demonstrated by the data in 
the first table and by figures 14 and 15. 
Section AB (fig. 14, the method of 
construction of which was given on 
p. 151) represents the positions of the 
water table on the dates indicated 
relative to its position on December 
12, 1913. Up to that time the water 
table had been going down, though 
slowly, for a month or two previous. 
So far as this section is concerned, 
December 23 might as well have been 
selected for the date of beginning, for 
the water in well 147 was then 50.38 
feet below the point of measurement, 
while on December 12 it was 50.60 
feet below the same point. On the 
afternoon of December 23 Alameda Creek began flowing for the 
first time during the season. On December 26 the water in 
well 147 had risen about 2 feet, and on December 29, as shown 
in the graph (fig. 14), it had risen more than 4 feet. This re- 
sponse was, however, shown only a very short distance to the 
south, the water level in well 153 having risen only about 6 




GEOUND-WATER RESOURCES OF NILES CONE, CAL. 



155 



inches on December 29. On January 4 the water in well 147 showed 
a further rise, and the response extended considerably farther south, 
though even at this date it practically died out within a distance of 
1 mile. Meanwhile the water table at the south end of the section 



Feet 

50 



Datum plane 



.•?•■■■" 



Datum plane 



t Feb. 24 
Feb. 18 

Jan. 29 



Jan. 10 



Dec. 28 
Dec. 15 



193 194191 187 185 198 181 172 162 161160 156 145 

Figure 17. — Graph showing fluctuation of water table along line H-E, Plate X. 

shown in figure 14 continued to sink slowly. The curve for each 
successive date shows the same slow progress toward the south. 
By studying the graph one may almost see the water creeping slowly 
southward from Alameda Creek. Even as late as March 12 the rise 



Feet 




210 211 208 207 204 205 170 169 166 165 159 157 

168 

Figure 18.— Graph showing fluctuation of water table along line I-J, Plate X. 



at the south end was almost negligible, although at the north end it 
amounted to nearly 15 feet. 

Section AC, just east of the fault (fig. 15), is of very different 
character from section AB, just west of the fault (fig. 14). In 



156 CONTRIBUTIONS TO HYDROLOGY OP UNITED STATES, 1914. 



section AC water is supplied from several sources, as is shown by 
the depressions between different drainage areas, but in section AB 
the water comes from a single source. These two sections are very 
close together in most places (PL X). At their north ends they 

start from practically the 
same point and at the 
south end of AB they 
are only about 300 feet 
apart. 

A well (169) just south 
of section AB showed a 
quick response to rain- 
fall and a very much 
greater rise than its near- 
est neighbor to the north, 
about 500 feet distant. 
This difference is thought 
to be due to a small leak 
through the fault plane 
near the well. The leak- 
age, however, is not suf- 
ficient to affect neigh- 
boring wells and may 
affect this one simply be- 
cause of its nearness to 
the point of leakage. The 
water contours for De- 
cember (Pl.X) mightsug- 
gest that there was a con- 
siderable leak through 
the fault dam where it 
crosses Alameda Creek, 
but the crowding of the 
contours at this point is 
thought to be due in 
large part to the fact 
that the Niles Sand & 
Gravel & Rock Co. is 
continually pumping water and turning it down the creek. This 
water flows for some distance beyond the fault dam and then rap- 
idly disappears. 

The profiles of the water table in section MN (fig. 20), which are 
based on levels instrumentally determined, show the true slope of 
the water table along this line and therefore the direction of move- 
ment of the ground water, or, rather, not the path of actual motion 




GROUND-WATER RESOURCES OF NILES CONE, CAL. 



157 



but the line of one of the two components 
into which the true motion can be resolved. 
The absolute motion at any given place, other 
things being equal, is determined by the di- 
rection of steepest slope. As surface water 
runs down a hill in the direction of steepest 
slope instead of following some line having 
less slope, just so ground water tends to move 
along the path of steepest slope unless fric- 
tion in this direction is so much greater that 
it neutralizes the effects of steeper slope. 
The exact position of this path of steepest 
slope can not be determined from a single 
section, but the single section MN, for ex- 
ample, shows that one component of the 
motion of the water is southward. 

The four concentric sections, Ci, C2, C3, and 
C4, shown in figures 21 to 24, although not 
controlled by levels, have the same general 
character as section MN. The general slope 
in each is toward the south, and the irregu- 
larities of this slope are aUke in character, 
occurring where they would be expected on 
account of character of the soil or relation to 
the drainage. These sections also show the 
lines of greatest flow and therefore of least 
resistance. They show two maxima — one 
along the present Alameda Creek, the other 
along '^Old Alameda Creek," or Sanjen de 
los Alisos — with a strong movement through- 
out the whole area lying between them. On 
either side of this interstream area the slope 
becomes more gentle and more nearly uni- 
form. In the region between wells 205 and 
207, however, the slope is abruptly reversed, 
indicating flow in a northerly direction. This 
is seen on four of the five profiles in section 
MN {fig. 20). The profile for December 23 
shows practical stagnation in the region be- 
tween wells 116 and 205, but with a sUght 
backward drift of the water. This movement 
is also indicated by the water contours for 
December shown on Plate X. 

The slight backward drift shown in this re- 
gion is beheved to be due to the heavier pump- 
ing in the more central portions of the Niles 





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ro 

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s 

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Ul 

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i 


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■ \ 1/ 




1 111 




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158 CONTRIBUTIONS TO HYDEOLOGY OF UNITED STATES, 1914. 

cone, and especially that of the People's Water Co. at Alvarado. As 
shown by later graphs and profiles and also by the water contours for 
February (PL X), the water in the region between Alameda Creek 
and well 205 coines from a northerly direction. But during the low- 
water season, and especially when there is heavy pumping to the 
north, the water table in this vicinity will be lowered so much that a 
slope toward the region of heavy pumping will be estabhshed and 
consequently a reversal of direction of movement of ground water 
will occur. 

The more abrupt slope near Niles was probably caused by the 
pumpage of the Niles Sand & Gravel & Pock Co. (p. 156) and perhaps 
by sUght leakage through the fault dam in the vicinity of Alameda 

Feet 



Feb. 4 



Jan. 29 
Jan. 19 



Dec. 28 
Dec. 10 




\_. 



Datunn plane 



130 131 128 136 151 152 161160 159 157 158 

Figure 21. — Graph showing fluctuation of water table along line Ci, Plate X. 

Creek. The slope near Alvarado was caused by heavy pumping by 
the People's Water Co. 

The conclusions reached are that the portions of Niles cone and the 
adjacent tract to the south covered by this report .lying west of the 
fault receive their water from Alameda Creek, and that the area east 
of the fault receives its water partly from Alameda Creek and partly 
from the smaller streams that discharge upon this area. 



CONTRIBUTIONS TO THE GROUND-WATER SUPPLY. 

The amount of ground water annually used can not exceed the 
difference between the amount added to the ground-water supply 
during an average season and the amount unavoidably lost each year. 
Indeed the yield on which it is safe to count is somewhat less than 
this difference, as it depends to a large extent on the more unfavor- 
able seasons. The amount of water percolating downward and join- 
ing the ground water in an area such as is here described depends on 



GEOUND-WATER RESOURCES OF NILES CONE, CAL. 



159 






a number of conditions, some of the most influential of which are the 
size and character of the drainage* basins tributary to the area, the 
amouat and distribution of the rainfall in these drainage basins, the 
topography of the area, the permeability and porosity of the materials 
underlying the area, and the 
elevation of the water table at 
the beginning of the replen- 
ishing season. In any given 
area all these conditions are 
constant except the rainfall, 
its distribution, and the posi- ^ 
tion of the water table. A I 
large amount and proper dis- ^ 
tribution of rainfall and a 
low position of the water I 
table are favorable to ground- \ 
water storage. ; 

An estimate was made of ] 
the amount of water added I 
during the season of 1913-14 \ 
to the underground supply \ 
of the Niles cone and that = 
part of the additional tract [ 
outhned on page 127 lying I 
west of the fault. This es- ; 
timate was made by multi- t 
plying the average rise of ^ 
the water table, in feet, by ! 
the percentage of pore space, \ 
and this product by the area, '■ 
in acres, the result being ex- 
pressed in acre-feet. The 
average rise of the water 
table was obtained by aver- 
aging the measured rise in 
125 weUs suhequaUy distrib- 
uted over the entire area 
west of the fault and found 

to be 11.32 feet. The po- "" ° ^ ^ ^ ^ I 

rosity was assumed to be 25 per cent. The area was esti- 
mated, by measuring with a planimeter on a photographic enlarge- 
ment of the United States Geological Survey topographic maps, at 
20,817 acres. An estimate based on these figures gives the supply 



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160 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1914. 



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added during the season of 1913-14 
as 58,912 acre-feet, exclusive of the 
amount withdrawn during the period 
of rising water. 

The assumption of 25 per cent 
porosity is beheved to be within rea- 
sonable limits of error. Mendenhall ^ 
in his studies of the San Joaquin 
Valley assumed a porosity of 20 per 
cent, but the materials of the San 
Joaquin Valley are finer on the aver- 
age than those dealt with here, and 
their available pore space is doubtless 
less. Buckley ^ determined the maxi- 
mum porosity of sandstone at more 
than 28 per cent. T. W. Espy ^ made 
porosity determinations of soils in 
the Livermore VaUey ranging from 
27.3 to 49.5 per cent, with a general 
average of 37.6 per cent, but it is 
believed that his method, that of 
pouring the soil into water and 
shaking, yields too high results . Lee * 
in certain tests with materials in 
Owens VaUey found approximately 
28 per cent of pore space. The 
materials in these tests were dry 
gravel, sand, and silt, which prob- 
ably have more pore space than the 
average sediments of the Niles cone 
region. 

The rapidity with which the ma- 
terials underlying the Niles cone 
absorb water is indicated in the fol- 
lowing table: ^ 

1 Mendenhall, W. C, Preliminary report on the ground 
waters of the San Joaquin Valley, Cal.: U. S. Geol. Sur- 
vey Water-supply Paper 222, p. 27, 1908. 

2 Buckley, E. R., Building and ornamental stones of 
Wisconsin: Wisconsin Geol. and Nat. Hist. Survey Bull. 
4, pp. 400-403, 1898. 

3 The future water supply of San Francisco from the 
conservation and use of its present resources, p. 202, Oct, 
31, 1912. 

* Lee, C. H., An intensive study of the water resources 
of a part of Owens Valley, Cal. : XJ. S. Geol. Survey Water- 
Supply Paper 294, diagram opposite p. 82, 1912. 

5 Lippincott, J. B., CaUfomia hydrography: U. S. Geol. 
Survey Water-Supply Paper 81, p. 33, 1903. Measure- 
ments made by W. W. Brier. 



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U 



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t5 



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LL-5-3DO 



GROUND-WATER RESOURCES OF NILES CONE, CAL. 
Discharge measurements of Alameda CreeJc, Alam£da County, Cal. 



161 





Discharge in second-feet. 


Date. 


Discharge in second-feet. 


Date. 


Niles dam, 

about 1^ 

miles above 

Niles. 


Three miles 
below Niles. 


Niles dam, 

about 1-^ 

miles above 

Niles. 


Three miles 
below Niles. 


Dec 18 1896 


38.68 
32.49 
30.94 


7.74 
6.19 

.77 


Jan. 11, 1897 


63.44 
67.25 
51.06. 


44 87 


Dec. 19, 1896 


Jan. 12, 1897 


40.23 


Dec. 20, 1896 


Jan. 18,1897 


34.04 









The rainfall during the season of 1913-14 was somewhat above the 
normal, as is shown by the following table. Moreover, it was well 
distributed, as is indicated by the monthly records given on pages 
135-141. The large and well-distributed rainfall and the low ground- 
water levels at the beginning of the season tended to make the 
additions to the ground-water supply in this year unusually large. 

Total precipitation July 1, 1913, to June 30, 1914, and seasonal averages for stations in 

the vicinity of Niles. 





Elevation 

above sea 

level. 


Precipitation. 


Station. 


July 1, 
19U, to 
June 30, 
1914, in- 
clusive. 


Seasonal 
average. 


Lick Observatory- 


Feet. 

4,209 

485 

64 

95 

19 

11 

87 

355 


Inches. 
35.61 
17.01 
24.12 
19.45 
20.35 
16.44 
18.91 
17.05 


Inches. 
31 42 


Livermore 


15.49 


Menlo Park 


a 16 85 


San Jose. . 


15 09 


Alvarado 


17 64 


Alviso . . 


15 01 


Niles 


18 61 




16.03 





a Seasonal average does not include 1913-14. 

The seasons 1911-12 and 1912-13 were probably the two succes- 
sively driest seasons on record, and the preceding sjeason (1910-11) 
was also unfavorable because more than half of the rain of the 
entire season fell during the month of January. This period repre- 
sents one of the most trying droughts the country has experienced 
and one in which the dependence on ground water was very great. 
However, a number of seasons on record had no greater precipitation 
than that of 1912-13. During the season of 1912-13 the ground 
water did not rise at all over a large part of the area and rose only 
from a fraction of a foot to 18 inches or 2 feet over the rest of it. 
The total amount of water added during this season, exclusive of 
withdrawals during the replenishing period, is estimated, from the 
data at hand, at only 2,600 acre-feet. 



162 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1914. 



It is concluded that the two years covered by the investigation, 
1912-13 and 1913-14, represent nearly extreme conditions, and that 
the range in annual contribution of ground water to the Niles cone 
and adjacent area west of the fault is between 2,600 and 59,000 acre- 
feet, or between somewhat wider hmits, exclusive of the withdrawals 
during the winter period of rising ground water. The range in 
ground-water contributions is therefore relatively much greater than 
the range in precipitation. 

WITHDRAWAL OF GROUND WATER. 

SPRING VALLEY WATER CO. 

About 16 milUon gallons a day,^ or 18,000 acre-feet a year, is with- 
drawn by the Spring Valley Water Co. from the Alameda Creek drain- 
age basin above Niles for the pubhc supply of San Francisco. If this 
water were not diverted a large part of it would ultimately reach 
the underground reservoir of the Niles cone. (See p. 135.) Two- 
thirds of this amount would be equivalent, on the assumption of 
25 per cent porosity, to a rise of the water table of about 2i feet a 
year. 

PEOPLE'S WATER CO. 

The People's Water Co. is ^^dthdr awing about 8 milhon gallons a 
day through its plant at Alvarado for the public supply of the trans- 
bay cities. Its average annual withdrawal during the five-year 
period 1904-1908, inclusive, was 1,541,000,000 gallons, or 4,730 
acre-feet, and dming the five-year period 1909-1913, inclusive, 
2,630,000,000 gaUons, or 8,075 acre-feet. Its withdrawal in the year 
1913 was 2,856,000,000 gallons, or 8,770 acre-feet — an amount 
sufficient to lower the water table about If feet a year if drawn 
entirely from the Alameda Creek supply. 

IRRIGATION. 

Water for irrigation in this area is obtained entirely from the under- 
ground reservoir. Data available are not sufficient to make a satis- 
factory estimate of the amount of ground water so used. The drought 
of 1911-12 and 1912-13 focused the attention of the whole community 
on irrigation, and it is safe to say that two-thirds of the irrigation wells 
in this region were sunk in the last three years. This development 
will continue to be rapid even in years of normal rainfall. Grain 
farming is rapidly being displaced by the raising of more profitable 
crops, such as alfaHa and tomatoes. The grain and grain-hay crops 
are almost never irrigated, but both alfalfa and tomatoes wiU be 
grown under irrigation. 

1 The future water supply of San Francisco from the conservation and use of its present resources, 
pp. 305-308, Oct. 31, 1912. 



GROUND-WATER RESOURCES OF NILES CONE^ CAL. 



163 



The following estimate of the amount of water needed for the 
irrigation of the crops grown on the Niles cone and vicinity has been 
prepared from the work of Frank Adams and is based on the acreage 
of the different crops as determined for 1913: 

Estimate of water needed for irrigating crops now grown on the Niles cone and vicinity. 
[Based on the work of Frank Adams, U. S. Dept. Agr. BuU. 158, pt. 2, and Bull. 254.] 



Character of crop. 


Depth of water needed 
in an average year 
(inches). 


Area 
(acres). 


Requirement 
(acre-feet). 




Maximum. 


Minimum. 


Maximum. 


Minimum. 




12 

18 
30 
30 
30 
12 
12 
12 
30 
30 
12 


8 

12 

24 

18 

24 

8 

8 

8 

24 

24 

8 


5,170 

2,900 

1,350 

2,430 

1,300 

380 

340 

75 

25 

65 

550 


5,170 

4,350 

3,375 

6,075 

3,250 

380 

340 

75 

50 

162 

550 


3,446 


Orchard 

Tomatoes 

Alfalfa 

Truck 


2,900 
2,700 
3,645 
2,600 


Potatoes 

Corn 


252 
226 


Sugar beets. . 


50 


Peas 


63 


Strawberries. . . 


130 


Nursery 


366 








14,585 


23,777 


16,378 



LOSS BY EVAPORATION ON THE SALT MARSH. 

Duryea ^ found the average annual loss by evaporation from a 
free water surface in three pans on dry land near San Jose, Cal., 
to be 56.7 inches for a period of two years, 1904 and 1905, and the 
average loss from two pans floating in water to be 44.7 inches for 
the same period. These experiments were made in the Santa Clara 
Valley about 18 miles from Niles and at about the same elevation. 
The conditions under which the experiments were made are there- 
fore similar to those on the Niles cone. 

Lee 2 found thi'ough his experiments in Owens Valley, Cal., that the 
evaporation from a deep tank set in the soil was 66.9 inches for the 
season 1910-11. He further found (Table 57) that the evaporation 
from a land surface covered with a good growth of salt grass where the 
depth to ground water was nearly 2 feet, conditions similar to those 
on the salt marsh adjacent to the Niles region, amounted to 42.67 
inches for the season of 1910-11. The evaporation from the land 
covered with salt grass was therefore 63 per cent of that from the 
free water surface in the tank set in the soil. 

By combining the results of Duryea with those of Lee it is possible 
to reach some estimate of the amount of ground water lost by evap- 
oration on the salt marsh at the foot of the Niles cone and adjacent 

1 Duryea, Edwin, jr., Eng. News, Feb. 29, 1912, p. 382. 

2 Lee, C.H., Anintensivestudyof the waterrecourcesofapartof Owens Valley, Cal.: U, S. Geol. Survey 
Water-Supply Paper 294, Table 51, p. 119, and Table 57, p. 122, 1912. 



164 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES^ 1914. 

area. This salt marsh borders San Francisco Bay and along the 
sloughs is wetted by the tides each day. The average evaporation 
from a free water surface on the marsh is therefore believed to be 
somewhat less than that shown by Duryea's land-pan records and 
somewhat more than that shown by his floating-pan records. The 
mean between these two is 50.7 inches a year, which is believed to 
represent approximately the evaporation that would occur if land 
pans were installed on the salt marsh. Lee's data show that the 
evaporation over the land covered with salt grass is 63 per cent of 
that from the land pan; and 63 per cent of 50.7 inches is 32 inches, 
or 2§ feet, which is approximately the depth of water that evapo- 
rates from the salt marsh each year. The area of the salt marsh is 
about 9,600 acres, and this area covered to a depth of 2§ feet is equiv- 
alent to 25,600 acre-feet. A part of the water that evaporates is 
sea water which enters through the sloughs and seeps into the banks 
of the sloughs, but the general observations which were made lead 
to the conclusion that most of it is shallow ground water supplied 
from Niles cone and adjacent tracts without passing beneath the 
denser clay beds. From the data at hand it seems reasonable to 
assume that the average annual loss of ground water by evaporation 
from the area under consideration is between 10,000 and 25,000 
acre-feet. 

SEEPAGE INTO THE BAY. 

An attempt was made to estimate the quantity of water lost 
through seepage into the bay by comparing the salinity of the bay 
water with that of sea water, but the data were found to be too 
meager to warrant drawing any conclusions. However, as the water 
beneath the bay is confined under a thick bed of dense clay, and 
the artesian pressure is slight, and as the water table has the very 
gentle slope shown b}^ the water contours (PL X), the loss by seepage 
into the bay from either deep or shallow sources is probably small. 

RELATION OF WITHDRAWALS TO CONTRIBUTIONS. 

The estimated contribution of about 59,000 acre-feet in the season 
of 1913-14 to the underground supply of the Niles cone and adjacent 
tract west of the fault is exclusive of the water pumped or otherwise 
withdrawn during the period of rising water. The withdrawals for 
irrigation and the loss by evaporation are almost entirely outside of 
this period, but a considerable part of the pumping by the People's 
Water Co. is done while the ground water is rising. 

The rising-water season of 1913-14 began in the later part of Decem- 
ber and closed near the end of April. The total amount of water 
pumped by the People's Water Co. from May 1 to December 31, 1913, 
was 6,000 acre-feet. The average annual loss by evaporation on the 



GROUND-WATER RESOURCES OF NILES CONE, CAL. 165 

salt marsh and seepage into the bay is probably between 10,000 and 
25,000 acre-feet. The annual requirement for irrigation of all the crops 
now grown, as computed in the table, is between 16,000 and 24,000 
acre-feet, the minimum requirement being approximately the quan- 
tity used for irrigation at the present time and the maximum the 
quantity that will probably be required in the near future. The total 
annual draft of ground water, exclusive of the withdrawals during 
the period of storage, would therefore be between 32,000 and 55,000 
acre-feet if the pumpage by the People's Water Co. remained the same 
as in 1913 and all the crops now under cultivation were irrigated. 

Interchange of ground water may take place between the Niles 
cone and the alluvial cones farther north, but it may be assumed that 
the supply of these cones is required for their own irrigation and is 
not available for pumping on the Niles cone. The annual storage 
would therefore be, in the most favorable years, between one and 
two times the annual requirement under the prescribed conditions, 
but in the least favorable years between one-tenth and one-twentieth 
of these requirements. The average annual contributions are prob- 
ably nearer the maximum than the minimum, but they are no doubt 
considerably less than the contributions of 1913-14. 

After making allowance for the uncertainties entering into several 
of the factors involved, it appears that the ground-water supply of 
the Niles cone and adjacent areas under consideration west of the 
fault is little if any greater than the amount required by present 
developments and is hardly adequate for the full irrigation of the 
area and the present diversions by the Spring Valley and People's 
water companies. If further diversions are necessary for the pubhc 
supplies of San Francisco or the transbay cities irrigation develop- 
ments will probably have to be arrested unless provision can be made 
for conserving and utilizing the large quantity of flood water which 
runs to waste into the bay through Alameda Creek. 

The northern portion of the vaUey area east of the fault has a 
larger ground-water supply in proportion to its extent than the area 
west of the fault. Its supply is believed to be at least adequate for 
the irrigation of the arable land that it contains, but from the vicin- 
ity of The Lagoon southward the materials of the water-bearing beds 
are of such a character that, in general, they do not yield water 
rapidly enough to meet the demands of irrigation. 

INCURSION OF SEA WATER. 

Some of the inhabitants of the region fear that with a lowering of 
the ground-water level the sea water wiU be drawn into the under- 
ground reservoir and the salt mai-sh will encroach upon the land. So 
far as is known to the writer, however, there is no definite basis for 
this fear — indeed, there is evidence that encroachment of the salt 



166 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES^ 1914. 

water is not likely to occur. The water of the bay is believed to be 
effectively shut off from the ground water. According to Mr. J. B. ' 
Rogers, a driller, coarse gravel containing a strong flow of good 
water was struck at a depth of about 196 feet in the well of the 
Morgan Oyster Co. off Mowrys Landing, and there are other fresh- 
water wells in the bay. One well on the shore of the bay at Ravens- 
wood, which flows at high tide but not at low tide, yields water having 
only 27 parts per milhon of chlorine. As most of the wells in the bay 
do not overflow at present it appears that the salt is kept out by the 
impervious character of the materials underlying the bay rather than 
by the excess pressure of the fresh water. A nearly impervious bed 
of blue clay hes below the bay and extends over the salt marsh. 
Below the bay it has a maximum thickness of at least 120 feet, but 
it thins in the direction of the land. This bed will probably prevent 
the entrance of salt water, except perhaps very locally, even if the 
head of the ground water is lowered below sea level. 

SUMMARY OF CONCLUSIONS. 

1. The ground water in the vicinity of Niles originates in the rain 
that falls upon the drainage basins tributary to this part of the Santa 
Clara Valley and to a small extent in the rain that falls upon the 
valley itself. 

2. The Niles-Irvington fault, which cuts off the reentrant of the 
valley between Niles and Irvington, has a profound effect on the 
surface drainage and on the circulation of the ground water. It is 
the cause of an escarpment, west of Tule Pond and The Lagoon, 
which intercepts and diverts southward all the mountain streams 
between Niles and Irvington except Alameda Creek. It has also 
produced an underground dam which prevents the passage of ground 
water from the east to the west side of the fault except in small 
amounts. 

3. The effectiveness of the fault as an underground dam is proved 
by the great differences that exist in the ground-water levels on 
opposite sides of it and also by the great differences in the interval 
required for the water levels on opposite sides to respond to rainfall. 

4. The area east of the fault receives a part of its ground water 
from Alameda Creek and a part from the smaller streams that dis- 
charge upon this area; an area west of the fault occupied by the 
Niles cone and a tract between this cone and a line extending ap- 
proximately from Irvington through a point on the Southern Pacific 
Railroad 1 mile southeast of Mowry station receives practically its 
entire ground-water supply from Alameda Creek. The area supplied 
by Alameda Creek west of the fault therefore covers somewhat more 
than 20,000 acres, exclusive of the salt marsh. 



GROUND- WATER RESOURCES OF NILES CONE, CAL. 167 

5. The contributions to the ground-water supply in the season of 
1913-14 were unusually large. According to observations at 125 
wells the water table in the area supplied by Alameda Creek west of 
the fault rose 1 1 .32 feet during the replenishing period of this season, 
and it is estimated that the total amount of ground water contributed 
to this area in the season of 1913-14 was about 59,000 acre-feet, 
exclusive of the amoimt withdrawn during the period of rising water. 

6. The contributions to the ground-water supply in the season of 
1912-13 were unusually small. Over a large part of the area supplied 
by Alameda Creek west of the fault the water table did not rise at 
all, and even in the most favored localities it generally rose less than 
2 feet. The total amount of ground water contributed to this area 
in the season of 1912-13 is estimated at only 2,600 acre-feet, exclu- 
sive of the amount withdrawn during the period of rising water. 

7. The annual contribution of groundwater to the Niles cone and 
the adjacent area under consideration west of the fault is therefore 
believed to range between 2,600 and 59,000 acre-feet, or between 
somewhat wider limits, exclusive of the withdrawals during the 
replenishing period. 

8. In the area supplied by Alameda Creek west of the fault ground 
water is withdrawn by pumping at the plant of the People's Water 
Co. for consumption in the transbay cities, by pumping at many 
small plants for local irrigation, and by unavoidable loss through 
evaporation on the lowlands bordering the bay and seepage into the 
bay. 

9. The annual withdrawals for consumption in the transbay cities 
averaged 4,730 acre-feet in the 5-year period 1904-1908, inclusive, 
8,075 acre-feet in the 5-year period 1909-1913, inclusive, and 8,770 
acre-feet in 1913, of which about 6,000 acre-feet was withdrawn 
outside of the replenishing period. 

10. The estimated annual requirement of ground water for irriga- 
tion of all crops now grown on the Niles cone and on the adjacent 
area supplied by Alameda Creek west of the fault is between 16,000 
and 24,000 acre-feet, the smaller quantity being approximately that 
now used for irrigation and the larger quantity that which will be 
required in the future. 

11. It is estimat^ed that the total annual withdrawal of ground water 
from the Niles cone and the adjacent area supphed by Alameda 
Creek west of the fault, excluding the withdrawals during the replen- 
ishing period but including the unavoidable loss through evaporation 
and seepage, would be 32,000 to 55,000 acre-feet if the pumpage for 
the transbay cities remained the same as in 1913 and all present 
crops were irrigated. 

12. About 18,000 acre-feet is annually withdrawn by the Spring 
Valley Water Co. from the Alameda drainage basin above Niles for 



168 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1!)14. 

consumption in San Francisco. If this water were not diverted a 
large part would ultimately reach the underground reservoir of the 
Niles cone. If the withdrawals for this purpose are increased the 
contributions to the ground-water supply of the Niles cone and 
adjacent tract wiU be further decreased. 

13. The ground-water supply of the Niles cone and the adjacent 
area west of the fault is Uttle if any greater than the amount required 
by present developments and is hardly adequate for the full irriga- 
tion of the area and the present-scale diversions by the Spring Valley 
and People's water companies. If further diversions are necessary 
for the public supplies of San Francisco or the transbay cities irri- 
gation developments wiU probably have to be arrested unless pro- 
vision can be made for conserving and utilizing the flood water which 
now runs to waste. 

14. The north end of the valley area east of the fault has a larger 
ground-water supply in proportion to its extent than the area west 
of the fault. Its supply is believed to be at least adequate for the 
irrigation of the arable land that it contains, but the portion of this 
area from the vicinity of The Lagoon southward is underlain by 
material that in general yields water too slowly for irrigation. 

15. There is little danger, even with heavy pumping, that the area 
under consideration will be seriously damaged by the encroachment 
of sea water. 

o 



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List Page(s): 

WATER-SUPPLY PAPER 345 PLATE IX 





ijggsari 



LEGEND 



Niles-Irvington fault 




Niles cone 

(The alluvial cone built by Alameda Creek) 
Groutid water supvlitid by Alanuda Creek 



m^ 
^ 



Tract west of the Niles-In'ington fault not 
belonging to the Niles cone but receiving its 
ground-water supply from Alameda Creek 
Ground-ivater entimates in this report are for the 
area comprising H) Die Niles cone and (2) this 
additional tract 



WATER SUPPLY PAPER 345 PLATE IX 




MAP OF THE DRAINAGE BASIN OF ALAMEDA CREEK AND ADJACENT AREAS 
Scale 1:250,000 



WATER-SUPPLY PAPER 345 PLATE X 



Q(^ lOe^S . '--ol CG 



_W*TER.SUPPLY PAPER 345 PLATE ) 




MAP OF THE NILES CONE AND ADJACENT AREAS, CAL-IFORNIA 



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LIBRARY OF CONGRESS 



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029 708 313 2 1 



